What?

Pew looked at over half a million Instagram, TikTok, and YouTube posts from February to April this year. These posts came from more than 6,000 health and wellness influencers, each with at least 100,000 followers. They found that 38% of the posts promoted a product, service, or subscription, and only 9% mentioned an outside source when making a health claim.

Supplements topped the list. About 66% of posts about supplements and over-the-counter medicines promoted something. The same was true for 52% of posts about longevity and 52% about nutrition.

This study has some limits. The accounts target a US audience, and an AI sorted the posts, and its results were checked against 600 posts reviewed by people. Pew only counted if a source was named. They didn’t check if the claims were true.

So what?

That last limit matters most.

Having a named source is just the first step in checking information. The book I reviewed lists about 1,730 references, yet it still gives doses I couldn’t trace to any study. Even if a post cites a source, it can still be wrong. If there’s no source, you have nothing to verify.

A sales pitch might still be accurate, but it also shows you who benefits if you believe it.

Medical tests can get costly. A 2025 study in JAMA Network Open looked at 982 Instagram and TikTok posts about five tests, like full-body MRIs and testosterone. They found that 87% mentioned a benefit, 15% mentioned a harm, and only 6% talked about overdiagnosis or overuse. Overdiagnosis means finding something real that would never have caused you any trouble. About 68% of the accounts had a financial interest. Posts from doctors were more likely to mention the risks.

If a test finds something, it can lead to more scans, referrals, and weeks of worry. Most posts don’t show you that side.

Now what?

Before you let a post influence what you buy, take, or test, ask yourself three questions.

• Who profits if I believe this? Check for things like a discount code, an affiliate link, or a clinic booking page.

• Is there a specific study, and did it test this dose on people like me? Look up the study name and the number. If the number isn’t in the study, it’s just someone’s guess.

• Who shouldn’t use this? If a post doesn’t mention any downsides or who should avoid it, you’re only seeing the sales pitch. For any test or drug, ask your doctor before you decide.

All three may take more time than the video, but they’re worth it.

Stay healthy.

Andre

It’s one of the few things I can suggest with hardly any risk. I never actually looked into it. It sounded reasonable, seemed safe, and came from a Stanford professor whose podcast I had followed for years.

His book, Protocols, was released on September 15. I pre-ordered it in April last year, as soon as the release date was announced. On his podcast, he described it as his life’s work, putting everything he had learned about the human body into one book.

When my copy arrived, I started reading right away. After about 20 pages, I paused and realized I should have asked myself an important question much earlier.

The book gives a specific dose for morning light: five to ten minutes on a clear day, fifteen if it’s cloudy, and thirty if it’s heavily overcast, all within the first hour after waking. I had shared some version of these numbers for years. Some of my advice came straight from his podcast. I just assumed every number was backed by a study.

I never questioned where those numbers actually came from.

So I decided to find out.

Where I’m coming from

Andrew Huberman has done something unusual for a scientist: he brought lab science into everyday life. In my circle, people often quote his episodes, and many have started paying more attention to their sleep, light, and exercise because of him. He’s been at this for years. I’m newer to this conversation, and I’m not offering new science. What I can add is a doctor’s perspective and a busy person’s perspective. The seven habits I share at the end of this piece all come from his book’s protocols. Most of my questions were about the numbers.

A book for the public needs to keep things simple. I do the same in this newsletter. If I qualified every sentence like a research paper, no one would keep reading.

“Get daylight in the morning” is a broad stroke. “5 to 10 minutes, 15 if it’s cloudy” is a dose. A dose sounds more precise, like someone tested it.

We all run on n=1, me included. I wanted to find out which parts of the book are backed by research, and which are just one person’s routine.

Twenty pages became a month

The book includes 47 protocols. Its notes list 1,126 numbered entries and about 1,730 references, with some repeats. Tracking all of that by hand would take a team months, so I used AI.

The AI matched each reference to its protocol, found 1,243 different papers in PubMed (the main medical research database), and I pulled 438 Huberman Lab podcast transcripts. Then I reviewed all 47 protocols myself, one by one, and confirmed each result. Because the searches were focused, I call this a physician’s audit, with plenty of tech help.

PubMed marks 109 of those 1,243 papers as randomized trials, which is about one in eleven. At least 99 were animal studies. These tags might miss some studies, so consider these numbers as minimums. This count just describes the references; it doesn’t judge each claim.

Out of the 47 protocols, 22 give a specific number of minutes, grams, or degrees that I couldn’t find any study to support.

Next, I added up the time. For each protocol, I estimated how many minutes it would take per week if you followed it exactly. The total came to 32 hours a week.

That number isn’t entirely fair to the book. Some actions are counted twice, one is a writing exercise you do only once, and another applies only after a loss. Even after removing those, you’d still need 25 hours a week, or about three and a half hours a day.

No one is expected to do all 47 protocols. You still have to choose what works for you. My sorting has 13 to keep, 18 worth trying, 7 that depend on your situation, and 9 I’d skip.

Where the minutes came from

The research behind morning light is real. In the UK Biobank, more than 400,000 adults reported how long they spent outdoors in daylight. Each extra hour went with lower odds of depression and fewer insomnia symptoms [1]. In 88,905 people who wore a light sensor for a week, those with the brightest days had lower mortality over the next 8 years. Those with the brightest nights had higher mortality [2].

Both studies are observational, so they can’t prove cause and effect. People who spend more time outside are often healthier for other reasons. Both studies measured light exposure over the whole day.

What I couldn’t find was any study testing those exact minutes. No research compared 5, 15, and 30 minutes based on cloud cover, or looked at the first hour after waking.

The claim about cortisol was even less solid. The book says morning sunlight can raise your cortisol peak by up to 50%. The first study it cites for this is a lab experiment with eight men who stayed awake all night, then sat under bright lab lights for three hours starting at 5 a.m. [3]. That’s a real result, but it’s very different from spending ten minutes on your balcony.

A reader texted me this week: “9 months out of the year, I get up in darkness. How important is this?”

It’s less important than the stopwatch suggests. And I know the problem too well.

Berlin has its qualities, but its winters aren’t one of them. In December, it’s dark from around 4 pm until 8 am, and the sky is mostly gray in between. You can go weeks without seeing blue sky. It hits my mood hard.

So we set up a 10,000 lux daylight lamp on our breakfast table. I work in front of it each morning. I’ve never measured my cortisol, but I feel it helps me get through the Berlin winter. The book also recommends a lamp for dark winters, and I agree.

The evidence is real, but only for a specific group. In people diagnosed with winter depression, light boxes worked better than placebo across 19 small randomized trials [4]. I don’t have that diagnosis. I just have Berlin.

The doctor’s take: keep the habit, but don’t worry about the exact timing. Try to get outside in daylight most days, and in the morning if it works for you. The research supports bright days and dark nights. The specific minutes are just someone’s best guess. If you have bipolar disorder or an eye condition, check with your doctor before using a light box.

Where my advice differs

Coffee first, and here the book and the data mostly agree. The book says to avoid caffeine in the 8 to 10 hours before bed. A meta-analysis of 24 studies found that caffeine cut sleep by 45 minutes, pooled across the doses tested. It estimated that a regular coffee should come at least 8.8 hours before bed [5]. With an 11 pm bedtime, that’s about 2 pm.

Where I’d differ is in the morning. If you tend to crash in the afternoon, the book suggests waiting 30 to 90 minutes after waking before your first cup. I couldn’t find any human trials on that delay. If you enjoy coffee right when you wake up, go ahead and have it.

Next is alcohol. The book says not to drink any alcohol in the eight hours before sleep. If you go to bed at 11 pm, that means your last drink would be at 3 pm. Most people don’t live that way.

I’d put it simply: no amount of alcohol has been shown to help you live longer. In 107 studies with more than 4.8 million people, drinking up to 24 grams a day (about two drinks) didn’t lower mortality compared to never drinking. At 45 grams a day, the risk was 19% higher; at 65 grams, 35% higher. For women, the risk started at even lower amounts [6].

Even one drink a day is linked to a higher cancer risk. The risk of one type of esophageal cancer goes up by 30%, mouth and throat cancer by 17%, and breast cancer in women by 5% [7]. These are relative increases, and the absolute risks remain small. Drinking also affects sleep: from about two drinks, REM sleep decreases [8].

Now for strength training. The protocol recommends three sessions a week, about an hour each. But a meta-analysis of cohort studies found the lowest mortality risk with just 30 to 60 minutes of strength training per week. More than that, the effect is unclear [9]. Two whole-body sessions of 20 to 30 minutes each are enough.

Personally, I do more than that.

My n of 1

I train six to seven hours a week. Almost every morning I’m up between 5:30 and 6 and in the gym for an hour.

That’s at least six times more than what the mortality data suggests. I started wrestling at six, made the youth national team, and won a national title. For as long as I can remember, training has helped me relax and start my day right. My hour in the gym is the one constant in my week, and it isn’t going anywhere.

It’s not easy. We have three kids, and our mornings are often hectic. My wife and I still debate whether to spend that hour helping everyone get ready. We haven’t settled it yet.

None of this is scientific evidence, but my n=1. I’d stand by it at my kitchen table, but I wouldn’t put it on a prescription pad.

My doctor’s take: many of the doses in the book seem like personal routines. I couldn’t find studies to support them. That’s fine as a personal rule, but it becomes a problem when it’s presented as advice for everyone.

Most health research looks at the average person, but no one is truly average. We all differ in how we sleep, what foods suit us, how warm we like our bedroom, and when we train best. The list goes on. Use studies as a starting point, then see what works for you. If something feels good and helps you, it might be right for you. If it makes you feel worse, stop, no matter what the protocol says.

One note from me as a doctor: feeling good and being safe aren’t always the same. A nightcap can feel good, and so can a tan. The basics are clear: don’t smoke, don’t get sunburned, and go easy on alcohol. Beyond that, listen to your body. Doing more is fine if you enjoy it. Just be clear about what’s backed by data and what’s your own choice.

Where low-risk stops

Most of the 47 protocols are low risk. A few aren’t, and that’s where my view as a doctor comes in.

When I say “try it,” people hear it as advice from a doctor. If something goes wrong, they’ll say the doctor told them to do it. That’s why I consider the risks first. In two cases, the risks outweigh the benefits.

Warming the bed before you wake. The book says to warm the bedroom in the last one to two hours before waking, and links a warmer body to more REM sleep. A review of temperature and sleep found that with normal bedding, heat increases time awake and reduces REM [10]. I found no test showing that warming up late adds REM. It also requires a heating timer or an expensive mattress cover. Keep the bedroom cool all night.

Sun on bare skin. The book recommends 20 to 30 minutes of sun on bare skin at least three times a week. It also says sunburn is bad and that you should cover up when the UV index is high. My question was about the reason it gives: that the data showed higher testosterone linked to sun exposure in men and women. I read the study. Most of the paper is in mice. The 19 volunteers who went into the sun had their hormone activity inferred from blood proteins. The measured testosterone came from health records of young men, compared across the seasons. No woman’s testosterone was measured [11].

Without a burn, UV is still UV. The WHO’s cancer agency classifies solar radiation as carcinogenic to humans, its strongest level of evidence [12]. Be outside every day. Cover your face and scalp. From a UV index of 3, I use SPF 50.

The rest of my cut list would take more space than I have today. I’ll share more about the full audit in the coming weeks.

Try this today

Back to those 25 hours. Here’s what made the cut. Most of these habits don’t take extra time. The training adds about two hours a week. In my Upward ARC framework, almost all of this falls under Activate: sleep, movement, and food.

• Fix your wake time. Keep it the same time seven days a week, with at least 7 hours in bed. If you can only do one thing, fix the wake time first, then the bedtime. In 60,977 people, the more regular sleepers had 20 to 48% lower mortality than the least regular fifth [13]. That’s an association.

• Have your last coffee about nine hours before bed. Enjoy your morning coffee whenever you want.

• Skip the nightcap. If you drink, have no more than two drinks, have them early in the evening, and not every night.

• Aim for about 7,000 steps a day. Compared to 2,000 steps, this was linked to a 47% lower risk of death in a meta-analysis of cohort studies [14]. Try taking calls while walking.

• Do strength training twice a week for 20 to 30 minutes each session. Focus on whole-body movements: push, pull, squat, hinge, and carry.

• Do cardio twice a week for about 75 minutes total, including one higher-intensity session. Brisk walking counts toward the WHO’s 150 minutes of moderate activity per week [15]. If you’re inactive, have heart, metabolic, or kidney disease, or get symptoms when you exercise, check with your doctor before doing intense sessions.

• Eat protein and plants, mostly unprocessed foods. Have protein at every main meal, vegetables at two meals, use olive oil as your main fat, and eat fish twice a week. Cut out sugary drinks, processed meats, and packaged snacks. One tip from my own routine, though not backed by a study: do your shopping and meal prep on the weekend.

The light I still recommend

I still encourage people to go outside in the morning. I just don’t mention the exact number of minutes anymore.

For the reader who wakes up in the dark nine months a year: when the sun rises, go for a walk. Research supports getting more daylight throughout the day. If winter affects your mood, try using a lamp at the breakfast table. That’s what works for me, but your experience may be different.

Is there a health rule you follow but have never actually checked? Reply and let me know. I read every message.

Stay healthy.

Andre

PS: If you know someone who follows a morning routine or protocol, please forward this to them. That’s how this newsletter grows, and it’s the only way I want it to.

PPS: If a friend sent you this, you can sign up for Under Load, my Sunday edition, at andreheeg.com.

References

[1] Burns, A. C., Saxena, R., Vetter, C., Phillips, A. J. K., Lane, J. M., & Cain, S. W. (2021). Time spent in outdoor light is associated with mood, sleep, and circadian rhythm-related outcomes: A cross-sectional and longitudinal study in over 400,000 UK Biobank participants. Journal of Affective Disorders, 295, 347–352. https://doi.org/10.1016/j.jad.2021.08.056

[2] Windred, D. P., Burns, A. C., Lane, J. M., Olivier, P., Rutter, M. K., Saxena, R., Phillips, A. J. K., & Cain, S. W. (2024). Brighter nights and darker days predict higher mortality risk: A prospective analysis of personal light exposure in >88,000 individuals. Proceedings of the National Academy of Sciences, 121(43), e2405924121. https://doi.org/10.1073/pnas.2405924121

[3] Leproult, R., Colecchia, E. F., L’Hermite-Balériaux, M., & Van Cauter, E. (2001). Transition from dim to bright light in the morning induces an immediate elevation of cortisol levels. Journal of Clinical Endocrinology & Metabolism, 86(1), 151–157. https://doi.org/10.1210/jcem.86.1.7102

[4] Pjrek, E., Friedrich, M.-E., Cambioli, L., Dold, M., Jäger, F., Komorowski, A., Lanzenberger, R., Kasper, S., & Winkler, D. (2020). The efficacy of light therapy in the treatment of seasonal affective disorder: A meta-analysis of randomized controlled trials. Psychotherapy and Psychosomatics, 89(1), 17–24. https://doi.org/10.1159/000502891

[5] Gardiner, C., Weakley, J., Burke, L. M., Roach, G. D., Sargent, C., Maniar, N., Townshend, A., & Halson, S. L. (2023). The effect of caffeine on subsequent sleep: A systematic review and meta-analysis. Sleep Medicine Reviews, 69, 101764. https://doi.org/10.1016/j.smrv.2023.101764

[6] Zhao, J., Stockwell, T., Naimi, T., Churchill, S., Clay, J., & Sherk, A. (2023). Association between daily alcohol intake and risk of all-cause mortality: A systematic review and meta-analyses. JAMA Network Open, 6(3), e236185. https://doi.org/10.1001/jamanetworkopen.2023.6185

[7] Bagnardi, V., Rota, M., Botteri, E., Tramacere, I., Islami, F., Fedirko, V., Scotti, L., Jenab, M., Turati, F., Pasquali, E., Pelucchi, C., Bellocco, R., Negri, E., Corrao, G., Rehm, J., Boffetta, P., & La Vecchia, C. (2013). Light alcohol drinking and cancer: A meta-analysis. Annals of Oncology, 24(2), 301–308. https://doi.org/10.1093/annonc/mds337

[8] Gardiner, C., Weakley, J., Burke, L. M., Roach, G. D., Sargent, C., Maniar, N., Huynh, M., Miller, D. J., Townshend, A., & Halson, S. L. (2025). The effect of alcohol on subsequent sleep in healthy adults: A systematic review and meta-analysis. Sleep Medicine Reviews, 80, 102030. https://doi.org/10.1016/j.smrv.2024.102030

[9] Momma, H., Kawakami, R., Honda, T., & Sawada, S. S. (2022). Muscle-strengthening activities are associated with lower risk and mortality in major non-communicable diseases: A systematic review and meta-analysis of cohort studies. British Journal of Sports Medicine, 56(13), 755–763. https://doi.org/10.1136/bjsports-2021-105061

[10] Okamoto-Mizuno, K., & Mizuno, K. (2012). Effects of thermal environment on sleep and circadian rhythm. Journal of Physiological Anthropology, 31, 14. https://doi.org/10.1186/1880-6805-31-14

[11] Parikh, R., Sorek, E., Parikh, S., Michael, K., Bikovski, L., Tshori, S., Shefer, G., Mingelgreen, S., Zornitzki, T., Knobler, H., Chodick, G., Mardamshina, M., Boonman, A., Kronfeld-Schor, N., Bar-Joseph, H., Ben-Yosef, D., Amir, H., Pavlovsky, M., Matz, H., … Levy, C. (2021). Skin exposure to UVB light induces a skin-brain-gonad axis and sexual behavior. Cell Reports, 36(8), 109579. https://doi.org/10.1016/j.celrep.2021.109579

[12] International Agency for Research on Cancer. (2012). Radiation (IARC Monographs on the Evaluation of Carcinogenic Risks to Humans, Vol. 100D). IARC.

[13] Windred, D. P., Burns, A. C., Lane, J. M., Saxena, R., Rutter, M. K., Cain, S. W., & Phillips, A. J. K. (2024). Sleep regularity is a stronger predictor of mortality risk than sleep duration: A prospective cohort study. Sleep, 47(1), zsad253. https://doi.org/10.1093/sleep/zsad253

[14] Ding, D., Nguyen, B., Nau, T., Luo, M., del Pozo Cruz, B., Dempsey, P. C., Munn, Z., Jefferis, B. J., Sherrington, C., Calleja, E. A., Chong, K. H., Davis, R., Francois, M. E., Tiedemann, A., Biddle, S. J. H., Okely, A., Bauman, A., Ekelund, U., Clare, P., & Owen, K. (2025). Daily steps and health outcomes in adults: A systematic review and dose-response meta-analysis. The Lancet Public Health, 10(8), e668–e681. https://doi.org/10.1016/S2468-2667(25)00164-1

[15] Bull, F. C., Al-Ansari, S. S., Biddle, S., Borodulin, K., Buman, M. P., Cardon, G., Carty, C., Chaput, J.-P., Chastin, S., Chou, R., Dempsey, P. C., DiPietro, L., Ekelund, U., Firth, J., Friedenreich, C. M., Garcia, L., Gichu, M., Jago, R., Katzmarzyk, P. T., … Willumsen, J. F. (2020). World Health Organization 2020 guidelines on physical activity and sedentary behaviour. British Journal of Sports Medicine, 54(24), 1451–1462. https://doi.org/10.1136/bjsports-2020-102955

What?

I focused on two sentences from that same episode, which came out on September 14.

The first sentence is the one I quoted: “If I just keep doing really hard things, I’m going to stay in control of my impulses.” I stopped there, but he continues: “As long as I also touch the goodness that’s there every day.” This is a personal rule for him, and he doesn’t mention any study to back it up.

The second sentence comes a few minutes earlier, and he presents it as scientific fact. He says, “We know for certain” that putting yourself in a high-adrenaline state “gets you better at dealing with high stress states.” He mentions ice baths, tough workouts, or very hot saunas as examples.

So what?

“Certain” feels like a strong word for the evidence available.

Let’s look at impulses first. In the most direct study I found, 174 people practiced self-control tasks for six weeks, but the training didn’t improve any measure of self-control. A 2017 meta-analysis of 33 studies found a small-to-medium benefit, but that effect shrank after correcting for publication bias. The most common training lasted two weeks, such as using your non-dominant hand.

Now for stress. In a 2025 trial, 404 adults did 29 days of Wim Hof breathing with cold exposure, or meditation. After each session, the cold-exposure groups reported feeling better able to handle stress than the meditators, and this feeling grew over the month. However, heart rate variability, resting heart rate, sleep quality, and fatigue did not differ. Since breathing and cold exposure were combined, the study can’t tell which part made the difference.

People do feel more able to cope right after a session. I believe that, because I feel it myself. Still, that’s a long way from being “certain.”

I’m not here to lecture anyone. A year ago, I wrote that controlled discomfort “makes you more resilient,” but I didn’t have a study to back that up either.

The finding I would actually act on is less exciting. Researchers pinged 205 adults for a week on a beeper and collected 7,827 desire reports. Those with the most self-control reported weaker desires and didn’t have to resist as often. They simply had fewer temptations to fight. This is just an observation, so it doesn’t prove that removing temptation works, but that’s still where I’d put my money.

I still take very hot saunas because I enjoy them. But I no longer expect them to help me keep my phone in my pocket.

Now what?

• Think of the one impulse that costs you the most. For me, it’s checking my phone when I’m with my kids. Consistent bedtime comes in second.

• Remove the cue for that impulse. For example, put your phone in another room. Leave the charger outside your bedroom.

• Write a simple if-then plan in one sentence. Mine is: “If I’m with the kids, then my phone is in another room or stays in the bag.” In 642 tests, plans like this worked, and they worked even better when people rehearsed them. So say your plan out loud twice.

Do the hard thing you enjoy. Then, put your phone somewhere else.

Stay healthy.

Andre

I opened the October issue of manager magazin. The cover story, “Das große Rauswerfen,” or “the great firing,” says tens of thousands of German executives are losing their jobs right now. [1]

The numbers back this up. In 2025, Germany had an average of 49,000 unemployed managers, up 14% from the previous year and the highest since 2015. [2] Three days after my flight, BMW announced it would cut its divisions and related management jobs by a fifth by mid-2027. [3] These figures are for Germany; I haven’t checked if it’s the same elsewhere.

As I read the article, many of these managers spent years coordinating other people’s work. They collected reports, passed on updates, and set agendas. Their companies asked them to do exactly that and paid them well for it. Now those layers are being removed. I don’t know why any one of them individually lost a job, and I won’t guess.

The article made me reflect. I looked around at people having coffee and snacks and found myself wondering: What am I doing to protect myself from a professional setback?

I was asking myself this in a lounge, a place designed so we don’t have to stand while waiting at the gate.

My kids make things all day

The honest answer might be: over the years, I’ve lost the skill of making things.

I watch my kids do it all day. They make things up. They try something, it fails, and they try again. They aren’t ashamed of any of it. They keep going until they can do it.

As we grow up, we start shaping how we see ourselves and how we want others to see us. After that, we focus on adding details and perfecting that image.

A corporate career works the same way. You learn what the job requires, and you get better and better at being a corporate leader. I’ve watched myself do it. It takes skill. It’s also something entirely different from sitting down and creating.

Getting promoted changes what you do. Now you use skills like making decisions, judging people, and handling conflict every day. Other skills quietly disappear from your routine. Someone else builds the first version or runs the first analysis.

By Friday, you can feel exhausted without having made anything yourself.

Last Sunday, I wrote about friends who are counting down their remaining working years. During that hour in the lounge, I asked myself a more specific question: What can the people around me still make themselves?

I believe that if you stop using a skill, it fades. I also think my approach to this has been wrong. Let me explain both points.

Use it or lose it

In 2025, 4 economists published the best data I found on this. [4]

A representative sample of German adults aged 16 to 65 took a reading test and a math test. About 3.5 years later, 3,263 of them took the tests again. On average, skills kept improving well into midlife. Reading peaked at age 46 and math at 41. That’s good news if you’re 45 and feel slower than before.

The researchers also asked how often people used these skills at work and at home. For math, this included things like calculating budgets, making charts and tables, and using formulas. For reading, it meant reading manuals, articles, emails, and memos. Then they divided the group in half.

For those who used their skills more often, there was no average decline at any age. For those who used them less, skills started to decline in their mid-30s.

The study only measured reading and math. It doesn’t directly address creativity, judgment, or leadership. The authors say their data show a pattern but can’t prove that using a skill protects it. Another possibility is that people with stronger skills end up in jobs where they use them more.

The study also doesn’t show that getting promoted causes any decline. Senior roles involve plenty of emails, memos, and articles, so many executives likely fall into the high-use group for reading. My observation is that tasks like making budgets and charts are often the first things you hand off after a promotion.

The doctor’s take: In my view, a senior job often takes away the chance to use certain skills. In my Upward ARC framework, this is the Capacity pillar: what you can still do, kept alive by actually doing it.

The hardship we buy

I have a theory about where our effort goes. When our jobs stop requiring us to make things, we look for challenges elsewhere.

The drive to the Baltic is one of the few times our kids get their screens. On Friday, all 3 were in the back with their shows. That gave Erna and me some peace, so we put on a podcast: Joe Rogan talking to the neuroscientist Andrew Huberman. [5]

At one point Huberman says, “If I just keep doing really hard things, I’m going to stay in control of my impulses.” Meanwhile, my three kids in the back seat were doing the opposite, and I let it happen.

I’m one of the people he’s talking to. I like pushing through things nobody asked me to do, and some of them are stupid. I could shower warm. I stand under the cold water for a minute anyway, and it does something to my mind. I do the same in the sauna. I stay when it gets uncomfortably hot.

I’m not alone in this. Michael Easter wrote a popular book called The Comfort Crisis, where he talks about the misogi. He learned it from Marcus Elliott, a Harvard-trained sports scientist. Once a year, Elliott chooses a challenge with two rules: it must be so hard you have a real 50% chance of finishing, and you can’t die. [6]

Jesse Itzler hired the Navy SEAL David Goggins to move in with him for a month and wrote a book about it. [7] Backyard ultra runners circle a 6.7-kilometer loop every hour until only one is left. The record is 119 loops, nearly 800 kilometers in close to 5 days. [8]

There is research about effort and value. In a 2011 experiment, researchers asked 52 students to bid on a plain IKEA storage box. Some had just built it themselves, while others got the same box already assembled. The builders bid $0.78 on average; the others bid $0.48. [9] This effect only appeared when people finished the job. If they built it and then took it apart, the effect disappeared. [9]

The doctor’s take: This is where I’ve been mistaken. A cold shower makes me feel like I’ve done something hard, but it doesn’t create anything. In the experiment, the extra value went to the box people built. The study didn’t test if this effect carries over to other things. I doubt it does, and I haven’t found any evidence that a cold shower or a misogi keeps your work skills sharp. Do hard things because you enjoy them.

Whether hard things train your control over your impulses is a separate question. I leave it open here.

The seat at the edge of the ring

Later in the same episode, Huberman tells a story from a boxing gym in San Diego where he used to spar on Wednesday nights. One man there looked sharp on the bags. He sat at the edge of the ring and gave everyone advice. Huberman kept inviting him in for a couple of rounds, and the man always had a reason to say no. In the end, the gym’s owner told him the man had probably not boxed a round since he was a kid. [5]

It’s easy to end up in that position. I’m talking about myself here. What got me out of it was writing. When I started posting on LinkedIn, my posts got 5 likes. That includes the colleagues who clicked to show support.

I lead an office, so when I speak, people listen. My role, my reputation, and a familiar audience all help with that. I don’t know how much my confidence relies on these factors, so I wanted to test it.

Online, none of that carries over. No one has to listen; it’s their choice. It’s uncomfortable every time. I put my ego aside, publish, and do it again the next week.

Writing taught me to go back and do things myself. That’s what I mean by creating. It’s the doing. It’s learning by building something on your own. Watching tutorials and collecting a certificate doesn’t count.

Since then I’ve been building. Here are 4 examples out of many. A task manager for people with ADHD. A workout planner for people who travel, which adjusts to the equipment in a hotel gym. My own app store. And a website for my writing, which I set up so that AI assistants can find and quote it. People call that GEO or AEO. It seems to be working. This week, someone told me he asked Gemini who to interview as an expert on a topic, and it suggested my name!

Building things has brought back the joy of creating. I lost that feeling over the years, but now I’m getting it back.

I chose to start over from the bottom. The people in that magazine article didn’t have that choice.

The doctor’s take: I don’t know of any study showing that returning to creating prepares you for job loss or protects you from restructuring. The German study is about keeping skills, which is a different issue. My view is that creating changes what you have in your hands the day after. That’s why I do it.

One more thought, and I’m leaving this open on purpose. A promotion lets you hand your tasks to others. AI lets us hand off even more of the thinking and doing, which probably makes us faster. I use it myself, even for things I build. What I can’t say is what happens over time if we become dependent on AI, or on the satisfaction of making something yourself. I don’t have an answer yet.

Try this today

What works is often small, and that’s what makes it tough. Doing a task you handed off years ago means you’ll be slower than the person who does it now. It also means asking someone junior to point out what’s wrong with your work. A cold shower costs me a minute of discomfort; this costs me some pride.

Take a moment to reflect. Write down three things you made yourself ten years ago but don’t make anymore. Circle the one you’d like to bring back. Or something new that’s not in your job description but forces you out of your comfort zone.

Create a first version yourself. Choose a small, useful task you’d usually delegate this week. It could be the first page of a memo or the first draft of a chart. Do it yourself from start to finish, without giving a briefing. Then ask someone who does this work daily for specific feedback.

Try a small misogi at work. Use Elliott’s first rule, but make it smaller. Choose a task where you’re unsure if you can still do it well, and where failure would only be embarrassing, not costly. Do it yourself, where others can see the result. His second rule still stands.

What my kids already know

Our oldest, Tilda, is 12 and wants to be a lawyer to help people. I admire her sense of right and wrong, and I hope she gets to follow that path.

Whatever Tilda, Magnus, and Karla choose to do, I want them to keep what they have now. They make things without worrying if they’re good at it yet. I hope they’ll always be willing to start over, even if it’s embarrassing.

That’s not something I can teach from a lounge chair.

What did you stop making yourself, and do you want it back? Reply and let me know. I read every message.

Stay healthy.

Andre

PS: If you know someone who is taking stock of their own work right now, forward this to them. That’s how this newsletter grows, and it’s the only way I want it to.

PPS: If a friend sent you this, you can get Under Load, my Sunday edition, here: andreheeg.com

References

[1] manager magazin. (2026, October). Das große Rauswerfen [Cover story]. manager magazin, (10/2026).

[2] Handelsblatt. (2026, January 14). Führungskräfte: Arbeitslosigkeit unter Managern erreicht Rekordniveau. Handelsblatt. https://www.handelsblatt.com/karriere/fuehrungskraefte-arbeitslosigkeit-unter-managern-erreicht-rekordniveau/100189439.html

[3] Deutsche Presse-Agentur. (2026, September 30). Bis Mitte 2027: BMW schrumpft Topmanagement um ein Fünftel. Autohaus. https://autohaus.de/nachrichten/autohersteller/bis-mitte-2027-bmw-schrumpft-topmanagement-um-ein-fuenftel-3911004

[4] Hanushek, E. A., Kinne, L., Witthöft, F., & Woessmann, L. (2025). Age and cognitive skills: Use it or lose it. Science Advances, 11(10), eads1560. https://doi.org/10.1126/sciadv.ads1560

[5] Rogan, J. (Host). (2026, September 14). Andrew Huberman (No. 2553) [Audio podcast episode]. In The Joe Rogan Experience.

[6] Roberts, R. (Host). (2021, July 19). Michael Easter on the comfort crisis [Audio podcast episode]. In EconTalk. Library of Economics and Liberty. https://www.econtalk.org/michael-easter-on-the-comfort-crisis/

[7] Itzler, J. (2015). Living with a SEAL: 31 days training with the toughest man on the planet. Center Street.

[8] Runner’s Tribe. (2025, June 26). Phil Gore breaks backyard ultra world record with 119 loops. https://runnerstribe.com/latest-news/phil-gore-breaks-backyard-ultra-world-record-with-119-loops/

[9] Norton, M. I., Mochon, D., & Ariely, D. (2011). The “IKEA effect”: When labor leads to love (Working Paper No. 11-091). Harvard Business School.

What?

A PLOS Medicine study published on September 17 tracked 95,559 UK Biobank adults for about 9 years. Each person wore a wrist sensor for a week, and an algorithm used their movement to estimate sleep stages. For every extra 47.6 minutes of estimated REM, there was a 46% lower risk of dementia and a 26% lower risk of heart failure. This is just an association, not proof. Also, the 80% drop in risk that some outlets reported for “Parkinson’s” actually refers to parkinsonism, which is a broader diagnosis.

So what?

These numbers have two main problems.

First, consider the wrist measurements. Compared with a sleep lab, the algorithm matched only moderately well and tended to undercount REM by about 17 minutes each night. The authors themselves call these numbers “movement-based estimates.” So, remember that your own wrist REM score is just an estimate too.

Second, there’s the timing. The strongest links are for dementia and parkinsonism, which are diseases that can disrupt sleep years before they are diagnosed. Wrist sensors can pick up more night waking as early as seven years before someone is diagnosed with Parkinson’s. The study authors removed cases from the first two years, and the links with dementia and parkinsonism still showed up. But two years is a short window for diseases that can develop over a decade or more. Also, a 2025 study combined data from five groups whose sleep was measured with electrodes (4,657 people in total) and found no link between sleep stages and dementia.

My read: this study does not show that increasing REM prevents disease. I wouldn’t rearrange a single night to improve a watch score on this evidence. Two things have been tested in sleep labs, and both cut REM: short nights and alcohol.

Now what?

• Try to get enough sleep each night. In a 2018 sleep-lab study, 35 adults who were limited to six hours in bed for a week lost about half an hour of REM sleep each night on average, but their deep sleep stayed about the same. REM sleep is longest in the last third of the night, which early alarms often cut short. If you have an early flight, try to go to bed earlier.

• Avoid drinking alcohol the night before an important day. A 2025 review of 27 studies found that REM sleep dropped even with low amounts of alcohol, which the authors define as about two standard drinks or less.

• Don’t focus on your tracker’s nightly REM number. Instead, focus on your average sleep time over the week and try to wake up at the same time every day.

• If your partner notices that you act out your dreams by punching, kicking, or shouting, talk to your doctor. REM sleep behavior disorder can show up years before Parkinson’s or similar conditions. It’s important to get it checked out.

Your watch will keep giving you a REM score, but you don’t have to pay attention to it.

Stay healthy.

Andre

Sources: PLOS Medicine paper · Skorucak, Sleep 2018 (PDF) · Yiallourou, Sleep 2025 · Gardiner, Sleep Med Rev 2025 · Postuma, Brain 2019 · ScienceDaily headline

She said it just before the waiter arrived. I’ve known her for over 15 years. We met early in our consulting days, and I’ve followed her career ever since. From the outside, she seemed to be doing great.

“I’m thinking about my next steps,” she said. “What I could do next.”

“Really? I’ve watched your career. It all looks very solid.”

“Yeah, yeah, no. All is good. There’s no need to do anything. I’m just thinking about where I can achieve the most while I still learn. And do something I believe in.”

We ordered. I looked down at the menu and stopped reading.

This was the third time in a few weeks I’d heard something like this. Three people who don’t know each other had described their motivation in different ways, but the feeling behind their words was the same.

In the next two weeks, I heard it two more times.

When friends share something in confidence, I keep it private. You won’t see any names, companies, or details here that could identify anyone.

Five people, one question

They were strong students who landed top jobs right out of university, mostly at big strategy firms. That’s how I met most of them. Over the next 20 years, some climbed the corporate ladder while others started their own companies.

None of them are in trouble. They could stay on the same path until retirement, and it would work.

None of them want to retire, either, and that surprised me most. Plenty of stories online are about people at 55 or 60 who have made their money and are planning an active retirement. But these five are still building and still have financial goals. They’re asking these questions while they’re still in the middle of their careers.

Most of us are Generation X. I always thought our deal was simple: keep your head down, build your credentials, and do the work, even when it isn’t exciting, because it pays off later. Purpose and passion were in the background, and no one asked if they should take the lead.

Now, twenty years later, they’re asking these questions. Each one does it quietly, as if it’s something to be embarrassed about.

A psychologist wrote it down in 1968

In all five conversations, some version of the same thought came up: How many more years do I want to keep doing this? How do I want to spend them? They had started counting backwards.

Bernice Neugarten, a psychologist at the University of Chicago, described it in 1968. She wrote: “Life is restructured in terms of time-left-to-live rather than time-since-birth.” She called the awareness that time is finite “a particularly conspicuous feature of middle age.” [1]

Five people, each in their own words, described what a researcher wrote down 58 years ago. Is this just a coincidence, a sign of the times, or simply our age?

From my perspective as a doctor, I think age is the main factor here. I haven’t found any strong data showing that people in their forties ask this question more now than they did ten years ago. This question has come up at this stage of life for almost 60 years, and my friends and I just reached it together. If you’re asking it, you’re right on time.

Counting backwards tells you one thing: your sense of how much time you have left has changed. Age can do that, but so can a health issue or an uncertain future. Try to figure out what changed for you before you answer the career question.

The world around us has changed. Based on a survey of employers, the World Economic Forum projects that 92 million jobs will disappear and 170 million new ones will be created by 2030. [2] Headlines like that make the future feel less certain. Even the people building AI can’t agree on whether we’ll have more or less work. In my parents’ time, doctors, lawyers, and managers could predict what the next few decades would look like. That’s not true anymore. Now, people talk about having portfolio careers and multiple sources of income. One job doesn’t feel as safe as it used to, and I think about that too.

Why the brain starts counting

Laura Carstensen at Stanford has spent decades studying what happens when people feel their time is limited. Her theory, called socioemotional selectivity, has a simple idea at its core. When time feels unlimited, we focus on gathering knowledge, contacts, options, and status. When time feels short, we focus on what matters most emotionally. [3]

This shift depends on how much time you think you have, no matter your age. Midlife is when the horizon often starts to feel closer.

Older adults usually prefer to spend time with people they know well. When researchers asked them to imagine a medical advance that added 20 years to their lives, that preference disappeared. [4] In Hong Kong, two months before the 1997 handover to China, when the city’s future suddenly looked uncertain, young adults made the same choices as older adults. One year after the handover, the age difference was back. [4] Illness moves the horizon too. Carstensen’s team saw the same shift in young men living with HIV. Their conclusion: “the perception of limited time, rather than chronological age, is the critical variable.” [5]

None of these studies looked at careers. Counting backwards is the same shift, applied to work. When the horizon moves closer, you start sorting your time by what matters to you. The AI headlines move that horizon for a lot of us, the way the handover moved it for those young adults in Hong Kong.

The back that started it

For me, it started with my back.

I know what pain feels like. I wrestled for 20 years, with more than ten of those years spent competing. Full-contact sports teach you about all kinds of pain. A bone hurts one way, a torn muscle another, and a shoulder about to pop out gives its own warning.

So when my back gave out, I knew this pain was different. It felt deeper than anything I’d experienced on the mat. As a doctor, I understood the anatomy, but I sensed this was about more than just the body.

My lowest point came in the summer of 2024. I was sitting on the terrace of our holiday home, on one of the big concrete steps leading down to the lawn. The sun was setting in front of me, turning the sky a deep orange you seem only to see near the sea. The windows behind me were open. My wife was getting the kids ready for bed, and the usual chaos had started. Karla was yelling about something, Magnus was running laps to burn off his last bit of energy, and Tilda was trying to find a room without the other two in it.

I sat on the step, looked at the lawn and trees, and started asking myself questions I’d avoided since my twenties. What am I doing? Why am I doing it? Who am I still trying to impress? Is it just about the money?

That was when I started counting backwards.

Take away the business class

Once I started asking these questions, I stripped away everything that comes with a senior job: the borrowed status of a company name, the title, the business-class seat, the nice hotels, the expensive dinners, and the way people treat you when you walk into a room. Over the years, all of that had become part of how I saw myself.

Then I wondered what would be left. What would I do if I could really choose? Building, helping, learning, creating: which one brings me the most satisfaction? How much of what I do is shaped by what others think? How much is about earning easy, safe money compared to facing an uncertain future?

And there was one question I couldn’t let go: in two or three generations, no one will remember my name. So why am I putting so much into something that won’t matter after I’m gone?

It took me a while to answer it.

Capacity is the part of my Upward ARC framework I think about most right now. It’s about what you can still learn, the skills you build, and the reserves your mind and body carry into later life. My friend at lunch put it simply: she wants to keep learning. Capacity is what makes that possible.

Why nobody says it out loud

Five people, the same question. Each told me in confidence and seemed to think they were the only one feeling this way. Some of that silence is just being careful. Usually, no one wants to share career doubts with colleagues.

Psychologists call this pluralistic ignorance. Most people in a group privately feel one way, and each of them assumes everyone else feels the opposite. I have seen this unfold in many leadership trainings I took part in. In the closing round, participants often named it their biggest takeaway.

Boards show it clearly, too. When companies performed poorly, outside directors underestimated how many of their fellow directors shared their doubts about the strategy. The doubts stayed unspoken, and the strategy stayed the same. [6]

I think the same thing happens with this question. Everyone at the table is wondering about it, but each person assumes everyone else is confident.

The word “crisis” makes things harder. Nobody wants to be seen as having a midlife crisis. In a US study of 724 adults, 26% said they’d had one, using the word for many experiences like divorce, career setbacks, and illness. Among people aged 49 to 53, 44% described a crisis involving physical decline, changing priorities, blocked achievement, and “shortened futures.” Another 16% felt trapped in an unsatisfying job and wanted to change careers “before it was too late.” The numbers in that age group were small, to be transparent. [7] My friends are calm, successful, and grateful. They want to choose their next steps on purpose.

Wanting to change, and staying

A German study followed 2,835 workers born in 1959 or 1965 over four years. One in ten changed profession. Another 17.6% wanted to change but didn’t. Most of that group wanted better conditions or less conflict between work and family, and they had worse mental health than the people who were content to stay. [8] The study can’t show which came first.

Work shows up in the body, too. A 1991 study followed 3,020 aircraft-industry workers for just over four years. Those who “hardly ever” enjoyed their job tasks were 2.5 times more likely to report a back injury than those who “almost always” did. [9] Those were very different jobs from ours, but I’ve stopped seeing my back and my work as separate issues.

Purpose affects health too. A 2026 meta-analysis of nearly 490,000 people found that having more purpose was linked to about a 15% lower risk of dying during follow-up, even after accounting for health habits and existing disease. [10] This is observational, and here, purpose means purpose in life. It doesn’t have to come from your job.

The honeymoon problem

Before you hand in your notice, consider what happens after a job change. Researchers found that when managers changed jobs voluntarily, their satisfaction rose at first, then fell back down. They called this the honeymoon-hangover effect. [11] The study didn’t look at moves into more meaningful work, and I don’t know of any good research showing which kind of change is best. Just changing your job title or company isn’t enough by itself, though.

As a doctor, here’s my take: chasing your passion while your family is worried about school fees isn’t a good idea. I wouldn’t do it, and I won’t recommend it. I have three kids in school, with university still ahead. Any answer to this question has to cover the household first. My friends are still building too, and we’re lucky to be asking this with some savings. Many people asking these questions have much less room to maneuver. So I plan for both: the household and whatever comes next.

And make sure you’re counting the right years. In Germany, the gap between life expectancy and healthy life expectancy was 10.8 years in 2019. [12] This gap spans a lifetime, so you can’t just subtract it from your next 20 years. But it’s a reminder that years and healthy years aren’t the same. Cardio fitness, strength, and sleep can help you make the most of the years you have.

Try this today

The backwards count. Take a sheet of paper and write down your age, the age you’d like to stop working full time, and the years in between. Then list two or three things your body needs to do well during those years, like carrying your bags through an airport or climbing four flights of stairs without stopping. Pick the one you’re least sure about and start working on it this week.

The five-year test. Carstensen’s research shows that having a shorter time horizon changes your priorities, so try shortening it on purpose. Write down what you’d do if you had only five working years left, then what you’d do if you had 20. The difference can show you what you might be putting off. This is just a thinking exercise. No one has tested it as a formal method.

The small test. Before making any big changes, run a small experiment in the direction you’re interested in. Have coffee with someone already doing that work or take on a side project. In my experience, a month of trying teaches you more than a year of thinking.

Tell one person. Pluralistic ignorance starts to fade when someone speaks up. Choose a peer you trust this week and share what you’ve been thinking. I bet they’ve been thinking about it too.

Put a number on your fear. When money worries are vague, they block every option. Figure out what your household and your kids’ schooling will need for the next five years. Once you have a number, you can make a plan.

What I’d tell her

At that lunch, I ordered a large portion with extra chicken because I had a protein goal to hit. Some habits don’t need a midlife review. We had a quick coffee afterward, and I thought about our conversation the entire bike ride home.

If I could sit down with her again, I’d tell her she’s right on schedule, and that it’s okay for this question to take center stage for a while. The thing she might have seen as a private flaw was something four other people were carrying too.

And I’d share what I realized after that evening on the terrace: my name will fade, but the work can last beyond me. Someone who can smile again. Something I built that still works.

What’s the question you haven’t said out loud yet? Feel free to reply. I read every message.

Stay healthy.

Andre

PS: If you know someone who’s doing well but quietly wondering what comes next, please forward this to them. They’ll understand why you sent it. That’s how this newsletter grows, and it’s the only way I want it to.

PPS: If a friend sent you this, you can subscribe to The Upward ARC at andreheeg.com.

References

[1] Neugarten, B. L. (1968). The awareness of middle age. In B. L. Neugarten (Ed.), Middle age and aging: A reader in social psychology (pp. 93–98). University of Chicago Press.

[2] World Economic Forum. (2025). The future of jobs report 2025. World Economic Forum. https://www.weforum.org/publications/the-future-of-jobs-report-2025/

[3] Carstensen, L. L., Isaacowitz, D. M., & Charles, S. T. (1999). Taking time seriously: A theory of socioemotional selectivity. American Psychologist, 54(3), 165–181. https://doi.org/10.1037/0003-066X.54.3.165

[4] Fung, H. H., Carstensen, L. L., & Lutz, A. M. (1999). Influence of time on social preferences: Implications for life-span development. Psychology and Aging, 14(4), 595–604. https://doi.org/10.1037/0882-7974.14.4.595

[5] Carstensen, L. L., & Fredrickson, B. L. (1998). Influence of HIV status and age on cognitive representations of others. Health Psychology, 17(6), 494–503. https://doi.org/10.1037/0278-6133.17.6.494

[6] Westphal, J. D., & Bednar, M. K. (2005). Pluralistic ignorance in corporate boards and firms’ strategic persistence in response to low firm performance. Administrative Science Quarterly, 50(2), 262–298. https://doi.org/10.2189/asqu.2005.50.2.262

[7] Wethington, E. (2000). Expecting stress: Americans and the “midlife crisis.” Motivation and Emotion, 24(2), 85–103. https://doi.org/10.1023/A:1005611230993

[8] Garthe, N., & Hasselhorn, H. M. (2022). Changes of profession, employer and work tasks in later working life: An empirical overview of staying and leaving. Ageing & Society, 42(10), 2393–2413. https://doi.org/10.1017/S0144686X21000088

[9] Bigos, S. J., Battié, M. C., Spengler, D. M., Fisher, L. D., Fordyce, W. E., Hansson, T. H., Nachemson, A. L., & Wortley, M. D. (1991). A prospective study of work perceptions and psychosocial factors affecting the report of back injury. Spine, 16(1), 1–6. https://doi.org/10.1097/00007632-199101000-00001

[10] Sutin, A. R., Zavala, D., Milad, E., Stephan, Y., Karakose, S., Brown, J., Terracciano, A., & Luchetti, M. (2026). Purpose in life and mortality: A meta-analysis of the published literature and individual-participant data of 488,765 participants followed for up to 32 years. Psychological Medicine, 56, e214. https://doi.org/10.1017/S0033291726104863

[11] Boswell, W. R., Boudreau, J. W., & Tichy, J. (2005). The relationship between employee job change and job satisfaction: The honeymoon-hangover effect. Journal of Applied Psychology, 90(5), 882–892. https://doi.org/10.1037/0021-9010.90.5.882

[12] Garmany, A., & Terzic, A. (2024). Global healthspan-lifespan gaps among 183 World Health Organization member states. JAMA Network Open, 7(12), e2450241. https://doi.org/10.1001/jamanetworkopen.2024.50241

What?

The actual evidence in people is much more limited. In a pilot study by Smith and colleagues, 20 people with Alzheimer’s took 20 grams of creatine each day for eight weeks. Their brain creatine levels rose by 11%, and some of their cognitive test scores improved.

But the study had no placebo group. So we can’t know if the improvements were due to creatine or just because people got better at taking the tests. The study, published in May 2025, mainly checked if this creatine routine was doable. It doesn’t prove a 30% drop in decline.

So what?

I need to correct myself here. In my September 2025 creatine update, I said you’d think more clearly within two weeks. That was too optimistic.

There could be some cognitive benefits. In a 2023 trial, 123 healthy adults took 5 grams a day for six weeks and showed a small possible improvement. Another trial in August 2026 gave 10 grams a day for 12 weeks to adults aged 45 to 65, and they also saw some benefits on certain cognitive tests. The senior author, Richard Kreider, is on the scientific advisory board of AlzChem, a company that makes creatine. The researchers called these cognitive results exploratory. Neither study shows that creatine protects against Alzheimer’s.

My advice is still similar to what I said in July: creatine is worth considering if you lift weights. In a placebo-controlled trial with 19 trained men, creatine helped them gain more strength over 12 weeks of lifting. The Alzheimer’s pilot study is just a first step for more research. Based on these results, I wouldn’t take more creatine for brain protection.

Now what?

Before you buy creatine or change how much you take:

• Think about what you want creatine to do for you. If you’re hoping it will sharpen your thinking, remember that benefit is still uncertain (but possible). I wouldn’t start taking it just to prevent Alzheimer’s based on what we know now.

• If you’re healthy, lift weights, and want to try creatine, go for plain creatine monohydrate at 3 to 5 grams a day. Check the label for how many grams are in each serving. This is the standard training dose, even on rest days.

• You don’t need to do a loading phase. In Hultman’s muscle study, taking 3 grams a day slowly increased creatine stores over about four weeks. There’s no need to use the 20-gram dose from the Alzheimer’s study to build up muscle creatine.

• If you have kidney disease, talk to your doctor before starting creatine. If you’re thinking about creatine for someone with Alzheimer’s, share the study with their doctor and ask for advice before changing any supplements or medications.

Stay healthy.

Andre

I stood in a busy, dusty square in Kathmandu, about a head taller than most people around me and likely the only Westerner using this kind of transport. Each morning, I took the minibusses to the hospital, where I worked in traumatology.

The square was unpaved and crowded with commuters. A minibus that seemed built for ten people could actually fit 15 or 18 if everyone squeezed together. I kept watching those men rest comfortably in a position I rarely saw adults use back home.

Why wasn’t I doing that?

When I first tried, I could only hold the position for a minute or two before my legs went numb. It took time to get deeper into the squat. The numbness was a sign to stop, and I wouldn’t suggest pushing through it. I had to build up slowly over months.

Now, I include the squat in my hip-mobility routine. I also notice how everyday movements can become awkward for adults, like getting out of a car or lowering themselves to the floor.

I’m 47, and I don’t want to give up on these movements without seeing if I can keep them.

Before you blame your birthday

As a doctor, I don’t think age alone explains why we lose certain movements. If getting out of a chair or reaching the floor is hard, I want to understand the reason.

I also think we’ve gotten too used to spending our days moving from one chair to another. If you spend most of your week sitting, make time for the movements you want to keep. Don’t wait until it becomes a problem.

For me, the squat is important. For you, it might be kneeling in the garden or getting down to play on the floor. Pick a movement you care about and use it as your reason to practice. There’s no single squat shape to follow. Your stance and body shape will affect how it looks.[1]

Flexibility is how much your joints can move. Strength is what lets you move through that range. Getting down into a position, staying steady, and getting back up all take practice, not just stretching.

Think about getting out of a low car. You need to swing your legs around, place your feet well, and stand up. Where does it feel awkward for you? Maybe moving your leg is hard, or maybe standing up is the tough part. Noticing these details helps you explain what’s difficult if you need help, though it won’t tell you the cause on its own.

I’d pick one everyday task like that before choosing which exercises to focus on. Be clear about what you want to do comfortably. Getting down to the floor and back up is a good goal, even if you need a hand for support. Start practicing from your current level. If you work with a trainer or physiotherapist, share your goal with them. It gives you both a clear target and a reason for your exercise choices.

The LIFE trial asked a question I care about: could people still walk 400 meters? Its 1,635 participants were sedentary adults aged 70–89 with physical limitations. Over an average of 2.6 years, a walking-led program, with strength, balance, and flexibility work, reduced loss of that ability from 35.5% to 30.1% compared with health education and gentle upper-body stretching. Serious medical events were 49.4% versus 45.7%, a statistically uncertain difference; most hospitalizations were judged unrelated to the program.[2]

A 2024 review also found that exercise programs led to fewer fall injuries in older adults. Almost all these programs included balance, functional movement, and strength exercises.[3] I want to keep these abilities in my routine long before I ever need a fall-prevention program.

A few minutes you can keep doing

A 2025 review pooled 189 studies involving 6,654 adults. Their average age was 26.8, and 61% were male. Regular static stretching, where you hold a position, improved flexibility.[4]

The analysis suggested that improvements leveled off at about 10 minutes of stretching per muscle group each week. That’s a helpful starting point. The authors question if this is a real limit, so I wouldn’t treat it as a strict rule or a ten-minute total for the whole body.

The analysis didn’t find differences in results by age. A July 2026 review found the same, though only three of its 79 trials focused on people aged 40–64.[5] I think it’s worth working on flexibility in midlife, and you can adjust how much you do based on your own response.

A separate 2025 review examined what changes when people stretch regularly. It found a small reduction in tissue stiffness and increased stretch tolerance after repeated static stretching.[6]

Here, stiffness means the resistance measured as tissues are stretched. Tolerance describes how much resistance a participant would accept near the end of a stretch test. Both changed alongside improvements in range of motion. The review found no clear increase in muscle-fiber bundle length, another proposed explanation.

The evidence for these reasons was rated as low or very low certainty, and most participants were young. We still don’t fully know how extra flexibility develops, especially as we get older.

For someone starting at home, I’d use comfort and ease of movement to guide the practice. Pain or a persistent restriction deserves a closer look.

I’d begin with just a few movements and make sure you have time to repeat them. A routine that takes a long appointment is tough to fit into a busy week. I want the first version to be simple enough that you can do it again later in the week.

Keep your strength training, too. A review of 36 studies found that resistance training improved flexibility, with larger gains in the higher-intensity programs. The comparison came from studies of uneven quality, none rated at low risk of bias.[7]

That’s enough reason for me to keep adding more challenging strength work to my plan. It doesn’t mean lifting heavier always leads to better mobility. Pick a weight you can control through a comfortable range, and increase it as you get stronger. Starting light is fine; the important thing is to keep challenging yourself as you improve.

I had an hour anyway

This Thursday, the whole family made a special trip to an embassy. I’ll share more about that in the coming months.

We got there at eight. The doors opened at nine, and a line had already started. Some people stood or leaned against the wall. I dropped into a deep squat and waited.

I was the only person in the queue doing it.

Years after Kathmandu, I found myself using the same squat outside an embassy. Even waiting for a visa became part of my exercise routine.

Try this today

My mobility drill takes about seven to nine minutes after a walk. Try starting three times a week. I picked the sequence and starting amounts as a practical suggestion, though this exact routine hasn’t been tested in a study.

If you’ve been sitting, walk for five to ten minutes first.[8] Keep a fixed support within reach, and stop if you feel pain, numbness, or tingling; recent surgery, restricted joint replacements, or recurrent falls call for an individually adapted routine.

The counter squat. Hold a fixed counter, keep your feet planted, and lower only as far as you can control. Hold for 20–30 seconds, stand up, and repeat once. Begin shallow if you need to. Five slow rises from a stable chair are another way to practice getting up and down.[9]

The half-kneel. With padding under the rear knee and your other foot in front, keep your trunk upright and gently shift forward until you feel a stretch at the front of the rear hip. Hold for 30 seconds twice on each side. If kneeling bothers your knees, take a supported standing split stance and gently shift forward instead.[8,10]

The wall calf stretch. Put your hands against a wall, step one foot back, and keep that heel down with the knee straight. Bend the front knee gently until you feel the rear calf stretch. Hold for 30 seconds twice on each side.[8]

The one-leg stand. Stand beside the counter with your eyes open, using your fingertips for support as needed and keeping your free foot close to the floor. Try two 20-second holds per side. Start with five to ten seconds if that’s enough of a challenge.[11,12]

Find a way to track your progress. For the one-leg stand, use the same counter and start with the same amount of time. If you begin with ten seconds and a firm grip on the counter, that’s your baseline. As it gets easier, try using a lighter touch, but keep the support nearby. Work up to the suggested hold time without feeling like you have to make it harder every time.[11,12]

Change only one thing at a time. If you’re focusing on using less hand support, don’t change how long you hold the position yet. This way, you can see what’s getting easier. After each session, jot down which exercise you did, how much help you needed, and if it felt comfortable. After a few weeks, check back on the everyday movement you picked.

Keep regular strength sessions in your week along with this drill, starting with at least two days if you’re building the habit.[9,12] The supported squat helps you practice the position. As you improve, your strength work should get a bit harder. If the routine feels easy, that’s your cue to make it more challenging.

In my Upward ARC framework, this is Activate, with Capacity as the reason to continue.

Starting something new deserves some kindness. If you need both hands to get out of a chair, use them. If a shallow squat takes focus, give it your attention. Adults should feel okay about being beginners at a physical skill. I count the supported version as a real session and would do it again.

Also, be generous with others you see moving awkwardly. Watching someone struggle to get out of a car doesn’t tell you much about their story. As a doctor, I’d want to know their background before giving advice. As someone writing about health, I want to encourage you not to ignore a difficulty you could manage.

I’m also willing to look a bit unusual myself. I enjoy finding ways to use the squat outside of my regular practice time.

After about ten minutes in the squat outside the embassy, I stood up and walked around a bit. I still had plenty of time for a few rounds of deep squat holds.

Is there a movement you’ve started avoiding because it feels awkward? Let me know. I read every message!

Stay healthy.

Andre

PS: If you know someone who blames a tough movement on getting older, please forward this to them. That’s how this newsletter grows, and it’s the only way I want it to.

PPS: If someone sent this to you, you can subscribe at andreheeg.com.

References

[1] Demers, E., Pendenza, J., Radevich, V., & Preuss, R. (2018). The effect of stance width and anthropometrics on joint range of motion in the lower extremities during a back squat. International Journal of Exercise Science, 11(1), 764–775. https://doi.org/10.70252/BWZE8275

[2] Pahor, M., Guralnik, J. M., Ambrosius, W. T., Blair, S., Bonds, D. E., Church, T. S., Espeland, M. A., Fielding, R. A., Gill, T. M., Groessl, E. J., King, A. C., Kritchevsky, S. B., Manini, T. M., McDermott, M. M., Miller, M. E., Newman, A. B., Rejeski, W. J., Sink, K. M., & Williamson, J. D. (2014). Effect of structured physical activity on prevention of major mobility disability in older adults: The LIFE study randomized clinical trial. JAMA, 311(23), 2387–2396. https://doi.org/10.1001/jama.2014.5616

[3] Guirguis-Blake, J. M., Perdue, L. A., Coppola, E. L., & Bean, S. I. (2024). Interventions to prevent falls in older adults: Updated evidence report and systematic review for the US Preventive Services Task Force. JAMA, 332(1), 58–69. https://doi.org/10.1001/jama.2024.4166

[4] Ingram, L. A., Tomkinson, G. R., d’Unienville, N. M. A., Gower, B., Gleadhill, S., Boyle, T., & Bennett, H. (2025). Optimising the dose of static stretching to improve flexibility: A systematic review, meta-analysis and multivariate meta-regression. Sports Medicine, 55(3), 597–617. https://doi.org/10.1007/s40279-024-02143-9

[5] Oba, K., Matsuo, S., Nakamura, M., Nakao, G., Fukaya, T., Mizuno, T., & Takeuchi, K. (2026). Moderating effects of individual characteristics and the target lower limb muscle group on flexibility adaptations to chronic static stretching in healthy individuals: A systematic review and meta-analysis of randomized controlled trials. Sports Medicine – Open, 12, Article 95. https://doi.org/10.1186/s40798-026-01066-1

[6] Ingram, L. A., Tomkinson, G. R., d’Unienville, N. M. A., Gower, B., Gleadhill, S., Boyle, T., & Bennett, H. (2025). Mechanisms underlying range of motion improvements following acute and chronic static stretching: A systematic review, meta-analysis and multivariate meta-regression. Sports Medicine, 55(6), 1449–1466. https://doi.org/10.1007/s40279-025-02204-7

[7] Favro, F., Roma, E., Gobbo, S., Bullo, V., Di Blasio, A., Cugusi, L., & Bergamin, M. (2025). The influence of resistance training on joint flexibility in healthy adults: A systematic review, meta-analysis, and meta-regression. Journal of Strength and Conditioning Research, 39(3), 386–397. https://doi.org/10.1519/JSC.0000000000005000

[8] Mayo Clinic Staff. (2024, June 18). A guide to basic stretches. Mayo Clinic. https://www.mayoclinic.org/healthy-lifestyle/fitness/in-depth/stretching/art-20546848

[9] National Health Service. (2024, February 28). Strength exercises. https://www.nhs.uk/live-well/exercise/strength-exercises/

[10] My Joint Health Hub. (n.d.). Iliopsoas syndrome. https://myjointhealthhub.bnssg.nhs.uk/hip-pain/iliopsoas-syndrome/

[11] National Health Service. (2023, November 7). Balance exercises. https://www.nhs.uk/live-well/exercise/balance-exercises/

[12] American College of Sports Medicine, Exercise is Medicine. (2024). Being active as we get older. https://acsm.org/wp-content/uploads/EIM_Being-Active-as-We-Get-Older_Flyer_English.pdf

Last week, Apple introduced a readiness score for the Watch Series 12 and Ultra 4. This score combines your activity, sleep, and vital signs into a number from 0 to 10, with advice like “Recover” or “Go For It.” According to Apple, it can help you plan your workouts and daily routine.

The new heart-rate sensor is backed by solid evidence. In a study by Apple with 1,254 participants, the Series 12 showed lower heart-rate errors than six competing devices during workouts and daily activities.

That study only measured heart rate. It did not test if following the readiness recommendations actually improves fitness. From the public sources I checked up to September 15, I did not find any trials that answer this question for Apple’s new score.

So what?

I want to correct something from my recovery series. I said heart rate variability, or HRV, was “the single most reliable indicator of recovery status.” That was too strong. I also gave too much credit to what a morning reading can tell us about brain recovery.

HRV measures the variation in time between heartbeats and can help guide training. In a 2021 trial by DeBlauw with 55 adults aged 18 to 35, the group using HRV had fewer hard training days. Both groups improved, but there was no clear difference in fitness gains. Since this was a small trial with a set training plan, it might have missed some differences.

This gives me a good reason to use HRV: it can help decide when to take it easy during a tough session. However, the trial doesn’t show that Apple’s score can make that choice.

I recommend using your training plan as a starting point. Use the score as a reminder to check your sleep, symptoms, and recent effort before making any changes.

Now what?

Before your next workout:

• Look at the details behind your score. See what changed in your sleep, activity, or vital signs. Make sure the recorded sleep and exercise match what you actually did.

• Write a sentence about how tired or sore you feel and how you have been sleeping. Add anything else that feels unusual.

• If you get a low score and also feel unusually tired or have slept poorly, pick the easier option in your plan. If your score and how you feel do not match, check the data before changing your session. If you are still unsure, go with a lighter workout.

• If you are worried about any symptoms, talk to a doctor before exercising, no matter what your score says. Apple’s instructions also note that the score doesn’t account for all health conditions or medications and should not be used alone to decide whether it is safe to exercise.

My practical advice is to take it easy if you are unsure about a session. This checklist has not been tested as a protocol for Apple’s score.

About 15 months ago, doctors put small ventilation tubes in her eardrums. After years of struggling to hear us, our youngest could finally hear well enough to complain.

She’s six now, but her hearing problems started when she was a toddler or even a baby.

She made noises, but the words we hoped for didn’t come. She didn’t say Mom or Dad. While other children started talking, we tried to figure out what was going on.

By age three or four, she had created her own way of speaking. We slowly figured out which sounds meant she was hungry or needed the bathroom. Our family understood her, but others did not.

Sometimes she tried to tell us something we just couldn’t understand. She would get upset, break down, and cry on the floor. I still remember those moments. Watching your child struggle to make you understand is heartbreaking.

We realized that some of her reactions meant she couldn’t hear us or didn’t understand. We kept talking to her, and she kept trying. Remembering this still hurts.

Karla had declined to participate

We’d seen ear specialists, but several exams didn’t give us any answers. Hearing tests were hard, partly because she was so young and partly because she’s Karla. She is a wild one, and she simply didn’t want to cooperate with the tests.

Eventually, we got her into an early-childhood assessment program in Berlin. The program included checks on her development and neurology. Another ear exam found fluid in both of her middle ears.

The medical name is otitis media with effusion, usually called glue ear. Fluid collects behind the eardrum without an acute ear infection and can interfere with sound passing through the middle ear. Those little tubes let air into that space [1,2].

I still don’t know why it took so long. She struggled for about three years, and those years felt endless to us. I can’t figure out what the earlier exams might have missed.

The doctor’s take: Persistent trouble with hearing or speech deserves an assessment that fits the child’s age and development [1]. A toddler’s refusal to cooperate leaves a question that still needs answering.

For those of us who spend much of our work listening to others, there’s an adult version of that same problem. You might get through a meeting but still struggle to follow what was said. In a senior job, you have to make decisions based on what you heard. At home, someone may need you to listen with more patience than you feel you have.

That’s why hearing should be part of any conversation about long-term performance. The effort it takes to listen can matter long before dementia is ever mentioned.

You got the words right

A standard hearing test checks how soft a sound you can hear at different pitches. But following someone speaking in background noise is much harder. Researchers call the mental work needed to overcome hearing problems listening effort [3].

In a 2025 study, Maggie Zink and colleagues compared adults aged 40–55 with adults aged 18–25. Everyone had normal results on standard hearing tests. In one moderately noisy condition, the middle-aged adults got the speech about as accurately as the younger ones, while changes in their pupils suggested greater effort after the sentences [4].

This was a small lab study, and the results depended on the test conditions and timing. They didn’t look at fatigue after a full workday. I would pay close attention to anyone who says they struggle in group conversations even if their hearing test is normal. NICE’s adult hearing guidelines also recognize that standard tests may not explain trouble hearing in noisy places [5].

If this sounds familiar, tell your hearing specialist exactly when and where you have trouble. It helps to explain whether it’s during a quiet talk, a group dinner, or a call with people talking at once [5].

In two lab experiments, Anastasios Sarampalis and his team tested young adults with normal hearing. Noise made it harder for them to remember words or respond to a visual task at the same time [6]. I think it’s important to consider the listening conditions before blaming every missed detail on memory problems.

We were adding English to this

Our two older children attend an international school. We speak German at home, but their friends, books, and Netflix choices make English a big part of their lives.

We enrolled Karla in the same kindergarten. She was already having trouble communicating, and now we were adding another language. We worried she might feel left out if she didn’t learn English like her siblings. We hoped she’d manage in either language, but we also wondered if we were making things harder for her.

The American Speech-Language-Hearing Association says that being multilingual doesn’t cause speech or language disorders [7]. Still, our decision about kindergarten left us with doubts. Parenting would be much easier if the research came with instructions for your own child.

Since the procedure, her speech has been catching up at a rate I still find astonishing. She practices a LOT, talking and asking questions until you can barely think straight.

A Cochrane review found that tubes can bring small improvements in hearing for children in the short and medium term, but it’s unclear if the benefits last [2]. Karla has also been getting speech therapy. Our experience may not be the same for every family.

The doctor’s take: I would look into ongoing listening problems in anyone who feels worn out by calls. I’d also check their workload and overall health. There are many things at work that an audiologist can’t solve.

It’s important to know what to treat. A five-year study of 587 working adults found that worse hearing in noisy places was linked to a small increase in the need to recover after work [8]. Another study showed that people who got their first hearing aids felt less listening-related fatigue than those who didn’t, but their overall tiredness didn’t always get better [9]. A workplace hearing program tested in 136 employees didn’t show much improvement in recovery needs compared to usual care over a year [10].

In my Upward ARC framework, hearing is part of Capacity. I want you to be able to follow the conversations at work and still have the patience for the ones at home.

The ears were a badge of honor

My own ears have a less emotional story. Wrestling damaged both of them, and now they’re different shapes.

In wrestling, deformed ears can signal that you’re a proper fighter. I was skeptical of this idea. It gives a sport that damages your ears a very convenient reason to celebrate the damage.

When it happened to my ears, I took extra care treating them. Now, my ears look normal unless you look closely. But regular earbuds always fell out. Whatever respect my ears earned in wrestling didn’t help when I just wanted to make a phone call.

Eventually, I spent a lot on custom earphones. I went to a hearing aid shop and had molds made of my ears. The finished earpieces looked like the monitors musicians use on stage, and each one fit its ear perfectly.

After that, I could hear small changes in people’s voices on the phone, even their breathing. With earphones that finally stayed in, listening on calls felt like a superpower.

These are high-end earphones, but they don’t amplify sound like hearing aids. I’m just sharing my excitement about the purchase, not making any health claims. If regular earbuds don’t stay in your ears either, I get why you’d spend extra for a custom pair.

You can also help improve the sound for everyone else. In interviews with 14 Swedish employees with hearing loss, clear audio, visible speakers, and taking turns made video meetings easier to follow. Some even found video meetings easier than meeting in person [11]. These are personal experiences, not measured productivity.

If you’re in a senior role, you can ask for better microphones and speakers, and encourage people not to talk over each other. Try using captions if they help, and ask anyone struggling what makes meetings easier for them [5,11].

For adults with mild to moderate hearing loss, a recent Cochrane review of 16 trials found that hearing aids probably help people listen and take part in daily life. Most participants were older adults [12]. A 2017 review found no clear drop in listening effort and rated the evidence as very low [13]. These are different results. At follow-up, I’d ask if the conversation that brought you in has become easier, and adjust the care plan based on what’s still hard [5].

What I’d promise someone worried about dementia

I wrote about dementia last August. If you’re concerned about your memory, hearing research gives you a reason to pay attention; and a number that’s easy to misinterpret.

ACHIEVE tested hearing care against health education in 977 adults aged 70–84 with untreated hearing loss. Across the full trial, hearing care did not slow decline in memory and thinking-test scores over three years [14].

The 48% result comes from a planned analysis of 238 participants recruited from a long-running heart study. Those who received hearing care declined 48% less on cognitive tests over three years than those who received health education. These recruits were older and had more risk factors than the other participants. Their health-education group also declined faster than the other trial controls [14].

That treatment difference was about one-fifth of a standard deviation, a measure of the spread in test scores. New cognitive impairment wasn’t significantly reduced, either overall or in the heart-study group. This outcome included diagnosed dementia, milder diagnosed thinking or memory problems, or a sustained drop in test scores [14].

A large Danish study found a link between hearing loss and later dementia [15]. But studies like this can miss differences in education or access to care. The ACHIEVE trial tested treatment, and its authors think that slower decline in healthier participants may have made it harder to see a benefit. Preventing dementia through hearing care in middle age is still unproven.

The doctor’s take: I’d address a hearing problem for the conversations it’s affecting today. The cognitive results add a reason to take it seriously as we age. I wouldn’t offer a 48% promise to someone sitting across from me.

Try this today

• Write down one situation where you often have trouble following speech. Schedule a hearing test and share that example, including any problems you have at home [5].

• On your next tough call, try changing one thing, like using a clearer microphone, turning on captions, or making sure people take turns. See if it helps you follow the conversation [5,11].

• If you already use hearing aids, mention any ongoing problems at your follow-up. Sometimes the fit needs adjusting, and your care plan should focus on what you still need to hear [5].

• Protect your hearing during loud activities by using proper ear protection and avoiding harmful noise. Distracting office noise and noise that can damage your hearing are two different issues [16].

If your hearing suddenly gets worse over three days or less, see a doctor within 24 hours [5].

First day of school

Karla still attends speech therapy, usually twice a week. Some words are hard for her, her sentences need improvement, and she’s still behind other kids her age.

Karla started school a week ago, with her preschool teachers fully recommending her for first grade. She was so proud, and I loved seeing her that way. A year and a half ago, I never would have imagined this.

I’m surprised it took me this long to write about her. For a long time, it felt too personal and too painful. Now, I think we’re far enough along to share our story, even though remembering her crying on the floor still hurts.

When do you find it hardest to follow a conversation? Reply and let me know. I read every message.

Stay healthy.

Andre

PS: If someone you know keeps struggling to follow calls or conversations, please forward this to them. This is how this newsletter grows, and it’s the only way I want it to.

PPS: If a friend sent you this, you can get Under Load, my Sunday edition, at

https://www.andreheeg.com

.

References

[1] National Institute for Health and Care Excellence. (2023, August 30). Otitis media with effusion in under 12s (NICE Guideline NG233). https://www.nice.org.uk/guidance/ng233/chapter/Recommendations

[2] MacKeith, S., Mulvaney, C. A., Galbraith, K., Webster, K. E., Connolly, R., Paing, A., Marom, T., Daniel, M., Venekamp, R. P., Rovers, M. M., & Schilder, A. G. M. (2023). Ventilation tubes (grommets) for otitis media with effusion (OME) in children. Cochrane Database of Systematic Reviews, 2023(11), Article CD015215. https://doi.org/10.1002/14651858.CD015215.pub2

[3] Pichora-Fuller, M. K., Kramer, S. E., Eckert, M. A., Edwards, B., Hornsby, B. W. Y., Humes, L. E., Lemke, U., Lunner, T., Matthen, M., Mackersie, C. L., Naylor, G., Phillips, N. A., Richter, M., Rudner, M., Sommers, M. S., Tremblay, K. L., & Wingfield, A. (2016). Hearing impairment and cognitive energy: The Framework for Understanding Effortful Listening (FUEL). Ear and Hearing, 37(Suppl. 1), 5S–27S. https://doi.org/10.1097/AUD.0000000000000312

[4] Zink, M. E., Zhen, L., McHaney, J. R., Klara, J., Yurasits, K., Cancel, V. E., Flemm, O., Mitchell, C., Datta, J., Chandresekaran, B., & Parthasarathy, A. (2025). Increased listening effort and cochlear neural degeneration underlie speech-in-noise deficits in normal-hearing middle-aged adults. eLife, 13, Article RP102823. https://doi.org/10.7554/eLife.102823

[5] National Institute for Health and Care Excellence. (2023, October 2). Hearing loss in adults: Assessment and management (NICE Guideline NG98). https://www.nice.org.uk/guidance/ng98/chapter/recommendations

[6] Sarampalis, A., Kalluri, S., Edwards, B., & Hafter, E. (2009). Objective measures of listening effort: Effects of background noise and noise reduction. Journal of Speech, Language, and Hearing Research, 52(5), 1230–1240. https://doi.org/10.1044/1092-4388(2009/08-0111)

[7] American Speech-Language-Hearing Association. (n.d.). Spoken language disorders [Practice Portal]. Retrieved September 11, 2026, from https://www.asha.org/practice-portal/clinical-topics/spoken-language-disorders/

[8] van Leeuwen, L. M., Goderie, T., van Wier, M. F., Lissenberg-Witte, B. I., Lemke, U., & Kramer, S. E. (2022). The longitudinal relationship between speech recognition in noise, need for recovery after work, job demand, and job control over a period of 5 years. Ear and Hearing, 43(2), 659–668. https://doi.org/10.1097/AUD.0000000000001127

[9] Holman, J. A., Drummond, A., & Naylor, G. (2021). Hearing aids reduce daily-life fatigue and increase social activity: A longitudinal study. Trends in Hearing, 25, Article 23312165211052786. https://doi.org/10.1177/23312165211052786

[10] Gussenhoven, A. H. M., Anema, J. R., Witte, B. I., Goverts, S. T., & Kramer, S. E. (2017). The effectiveness of a vocational enablement protocol for employees with hearing difficulties: Results of a randomized controlled trial. Trends in Hearing, 21, Article 2331216517692304. https://doi.org/10.1177/2331216517692304

[11] Marsja, E., Signoret, C., & Stenbäck, V. (2026). The digital workplace and meeting accessibility: A qualitative study on listening effort in video meetings for employees with hearing loss. WORK, 84(1), 197–209. https://doi.org/10.1177/10519815251398498

[12] Ferguson, M. A., Sarant, J. Z., Bennett, R. J., McIlhiney, P., Badcock, N., & Bothe, E. (2026). Hearing aids for mild to moderate hearing loss in adults. Cochrane Database of Systematic Reviews, 2026(8), Article CD012023. https://doi.org/10.1002/14651858.CD012023.pub3

[13] Ohlenforst, B., Zekveld, A. A., Jansma, E. P., Wang, Y., Naylor, G., Lorens, A., Lunner, T., & Kramer, S. E. (2017). Effects of hearing impairment and hearing aid amplification on listening effort: A systematic review. Ear and Hearing, 38(3), 267–281. https://doi.org/10.1097/AUD.0000000000000396

[14] Lin, F. R., Pike, J. R., Albert, M. S., Arnold, M., Burgard, S., Chisolm, T., Couper, D., Deal, J. A., Goman, A. M., Glynn, N. W., Gmelin, T., Gravens-Mueller, L., Hayden, K. M., Huang, A. R., Knopman, D., Mitchell, C. M., Mosley, T., Pankow, J. S., Reed, N. S., . . . ACHIEVE Collaborative Research Group. (2023). Hearing intervention versus health education control to reduce cognitive decline in older adults with hearing loss in the USA (ACHIEVE): A multicentre, randomised controlled trial. The Lancet, 402(10404), 786–797. https://doi.org/10.1016/S0140-6736(23)01406-X

[15] Cantuaria, M. L., Pedersen, E. R., Waldorff, F. B., Wermuth, L., Pedersen, K. M., Poulsen, A. H., Raaschou-Nielsen, O., Sørensen, M., & Schmidt, J. H. (2024). Hearing loss, hearing aid use, and risk of dementia in older adults. JAMA Otolaryngology–Head & Neck Surgery, 150(2), 157–164. https://doi.org/10.1001/jamaoto.2023.3509

[16] National Institute on Deafness and Other Communication Disorders. (2025, April 16). Noise-induced hearing loss. https://www.nidcd.nih.gov/health/noise-induced-hearing-loss

What?

On September 2, a team at Berkeley reported that semaglutide, the drug in Ozempic and Wegovy, increased the median lifespan of older female mice. Their median lifespan rose from 742 days to 834 days, a gain of 92 days, or about 12%. The treatment began when the mice were 20 months old, which is similar to a woman in her sixties. These mice were healthy, not obese.

The drug reduced the mice’s food intake by 24%. To compare, the team put 10 mice on the drug and 10 others on a diet with the same 24% reduction, then followed both groups for five months. The mice given the drug did better in three areas: exploratory drive, spatial memory, and blood sugar control. This research was publicly funded, and the University of California has applied for a patent to use these drugs for healthy aging.

So what?

Calorie restriction has increased lifespan in many lab animal studies. But keeping up a 24% reduction is tough for people: those in the CALERIE study, assigned to 25% restriction, managed about 12% over two years. In mice, semaglutide matched the food reduction and led to better results in three functional areas. However, they tested its survival benefit only against untreated controls.

This is the first longevity result in a while that I find truly interesting. The key comparison (drug versus diet for survival) is still ongoing, and they haven’t reported results yet. Nir Barzilai, a longevity researcher at the Albert Einstein College of Medicine who wasn’t involved in the study, put it well: “Maybe calorie restriction increases the lifespan more? The data is not there, and it bugs me.” When asked why the drug outperformed the diet on those three measures, Danica Chen, who led the study, replied, “The short answer is: we don’t know yet.”

The study only used female mice of one strain, all living in cages. While it measured muscle function, it didn’t address a question I often see in practice: what happens when people combine the drug with progressive resistance training and enough protein.

Now what?

If you’re already taking semaglutide for a medical reason, this mouse study doesn’t give you any reason to change or stop your treatment. Keep progressive resistance training in your routine and talk to your doctor about making sure you get enough protein.

If you’re thinking about using semaglutide to slow aging, keep in mind that no randomized trial has tested it for human aging or used lifespan or healthspan as the main goal. The SELECT trial found fewer deaths in people at high risk for heart problems, but it wasn’t a longevity study.

The main evidence for humans is in cardiovascular risk, so that’s what you should discuss with your doctor. In the trial, 17,604 adults with heart disease, a BMI of 27 or higher, and no diabetes saw major heart events drop from 8.0% to 6.5% over about three years. Novo Nordisk, the company that sells the drug, funded the study.

The next time you see a claim that something “extends lifespan,” check which species, the sex, and the age at first dose before looking at the percentage. It only takes a few seconds and helps you make sense of most claims.

I’ll share more on this topic when the results from the ongoing survival comparison are available.

Stay healthy.

Andre
​

People turned and laughed. We were staying at a hotel for a week of leadership training, a program I respected because of the commitment it required. Both the morning session and my eating window started at 8:00.

I took the eggs from the breakfast buffet because I was hungry (and pragmatic). I told everyone it was my time to eat, don’t mind me, and then started breakfast in front of them.

I still understand why that rule is appealing. With 16:8, you eat during an 8-hour window and fast for the other 16. Once you pick your hours, you have fewer decisions to make. That can help if you want to eat less.

The problem is expecting that one rule to deliver all the benefits you’ve heard about fasting.

People have asked for my opinion twice in the last two weeks. My answer always starts with their goal. Someone who wants to lose weight needs a different approach than someone focused on living longer. At 47, with an unstable shoulder and a back that acts up if I stop training, I have my own priorities.

Give the eating window a job

If a daily eating window helps you eat fewer calories without worrying about food all morning, it’s a useful tool. You can see if it’s working by watching your eating habits and your weight.

You can also lose weight without it. In a year-long trial, Liu and colleagues gave 139 adults with obesity the same calorie target. Those who also ate between 8 a.m. and 4 p.m. lost 8.0 kg; those cutting calories without the window lost 6.3 kg. The researchers’ statistical analysis estimated an additional 1.8 kg of weight loss with the window, though the difference wasn’t statistically significant (P = 0.11) [1].

That P value needs some explanation. If the eating window adds no real benefit, a difference this big could still show up by chance in about 11 out of 100 similar studies. Researchers usually use 5 out of 100 as their cutoff. In this case, they couldn’t be sure the extra benefit wasn’t just due to chance.

Maruthur and colleagues tested the timing more directly by providing the same calories to both groups for 12 weeks. An early 10-hour window produced no detectable extra weight loss or improvement in blood-sugar control compared with usual eating [2]. The 41 participants had obesity and prediabetes or diet-controlled diabetes, so this answers a question about that schedule in that population.

As a doctor, I think a daily eating window is helpful if it makes it easier to manage how much you eat. I wouldn’t add it to a diet that’s already working, just to get extra weight loss from changing meal times.

There is a stronger weight-loss result for a more demanding schedule. In 4:3 fasting, you eat normally on 4 days of the week and cut your usual calories by about 80% on the other 3, with at least one normal eating day between them. Catenacci and colleagues assigned 165 adults with overweight or obesity to that approach or daily calorie restriction. After a year, those assigned to 4:3 had lost 2.89 kg more [3].

The estimate isn’t exact: the 95% confidence interval, which shows the range of results that fit the data, goes from 0.14 to 5.65 kg of extra weight loss. Both groups had the same weekly calorie goal, coaching, and activity targets. In reality, the fasting group ended up eating fewer calories, which might explain why they lost more weight.

It comes down to “it depends.” If your goal is weight loss and that approach fits your life, go for it. Skipping breakfast until noon is a different kind of commitment and needs separate evidence.

Alternate-day fasting has also been studied on its own. In a review of 99 trials, it was the only fasting method that showed a clear advantage over daily calorie restriction, with an average difference of 1.29 kg. However, this advantage disappeared in the 17 trials that lasted at least 24 weeks [4].

I came back to fasting for a different reason

I already knew that eating less could help me lose weight. Later, I became interested in autophagy, the process where cells break down and reuse old or damaged parts. Learning about autophagy and longevity led me back to fasting with a 16:8 schedule.

That’s a good reason to put up with hunger. You hope something helpful is happening in your body while you wait to eat.

There’s a lot of science behind autophagy. Yoshinori Ohsumi won the 2016 Nobel Prize in Physiology or Medicine for discovering how autophagy works in baker’s yeast [5]. Figuring out how many hours of fasting trigger this process in people is a different research challenge.

Researchers can measure the process as it moves through human white blood cells. They call this autophagic flux. In 2017, Pietrocola and colleagues used a laboratory test that compared cells with and without a substance that blocks their breakdown machinery. Among volunteers fasting for up to 4 days, one type of white blood cell showed signs of activated autophagy [6].

The biggest nutrition trial using this method followed 121 adults with obesity for six months. They fasted for 20 hours on three days each week. An analysis after data collection found a difference compared to standard care, but the fasting group’s improvement wasn’t statistically significant. Some of the difference may have come from the comparison group getting worse [7].

Krista Varady, a fasting researcher at the University of Illinois Chicago, puts the uncertainty about timing plainly:

“We just don’t know the hours of fasting; we don’t know the level of nutrient deprivation with carbs or protein that’s required to induce it” [8].

The fasting app Zero claims autophagy increases after 16 hours. Fastic says intermittent fasting activates autophagy and can help you stay in your prime years longer. Both apps sell subscriptions [9,10].

Fasting might trigger autophagy, but no study has shown exactly how many hours are needed. As a doctor, I wouldn’t suggest using an eating window just for autophagy.

My body needs something different now

When I was 16, I would go even without water before wrestling weigh-ins.

By that point, I had spent weeks cutting calories. In the last days, I ate very little, sometimes just broth, sometimes nothing at all. On the final day, I used the sauna to sweat off the last kilogram.

The method brought the number on the scale down. It also belongs to a dangerous part of wrestling’s history. In late 1997, 3 previously healthy college wrestlers in different states died while rapidly cutting weight. All had restricted food and fluid and tried to maximize sweating; they developed fatal overheating [11]. That combination of dehydration and heat is distinct from restricting the hours you eat. Obviously.

Now, I need enough strength to keep training despite the injuries I’ve picked up. My right shoulder has dislocated several times, even after surgery, and is still unstable. I believe keeping the muscles around it strong helps keep it in place.

My back is another reason I keep lifting weights. When I go on holiday and skip the gym for a couple of weeks, I feel my body get weaker, notice more back pain and twitching, and then feel better once I get back to regular weight training.

Some of that might be mental. This is just my own observation. I’ve never actually measured muscle loss from a training pause or fasting.

Keeping my strength up is now more important to me than squeezing my meals into a shorter window.

When you read a claim about fasting and muscle, check what the researchers measured. A body scan’s fat-free mass includes water and other tissue as well as muscle. Moro and colleagues followed trained men for a year, with 10 in each group. The normal-diet group gained fat-free mass; the researchers couldn’t distinguish the 16:8 group’s change from chance [12].

The results differed between the groups, and the window group reported eating less. These findings are worth noting, but they don’t prove that fasting caused the men to lose muscle.

There’s also evidence that you can gain muscle while eating within a window. In an eight-week trial, women who lifted weights and ate about 1.6 grams of protein per kilogram of body weight each day gained 2% to 3% fat-free mass in all groups, with no clear difference between them [13]. It was a small study: only 24 of 40 women qualified for that analysis, and a supplement company funded it.

To me, these findings show it’s important to focus on what you eat during your window. My clinical advice is to make sure you get enough training and protein before you start limiting your meal times. The way I handle protein depends on how much I’m training, and I will write a refresher on protein soon.

In my Upward ARC framework, nutrition is part of the Activate step. I judge it partly by whether it lets me keep training and stay strong with the body I have.

Try this today

• For weight loss, see if a daily eating window helps you eat less and fits your routine. Think about the stricter 4:3 schedule separately.

• If you’re only keeping an eating window to reach a certain hour for autophagy, it’s worth rethinking that choice.

• If your goal is to stay strong, make sure you have enough food and time for training. A shorter eating window should fit around those needs.

You still have to get through your day

When I used an eating window, I often crashed in the afternoon. Having a protein-rich breakfast after training worked better for me.

A review of 71 studies with 3,484 healthy adults found no clear difference in thinking skills between fasting and eating. Most fasts lasted 12 hours, but longer fasts showed small declines [14]. Your own workday is a good way to see if the schedule helps you focus or just leaves you hungry and distracted.

In 17 trials, fasting and daily calorie restriction didn’t show a clear difference in hunger or fullness, though all the studies had some bias concerns [15]. If you feel better using an eating window, that should count in your decision too.

My advice is to stop forcing yourself to stick to an eating window if you spend your mornings thinking about food, crash in the afternoon, or keep missing dinners you want to attend. I’d count business dinners just as much as family ones.

I usually finish dinner two to three hours before bed. There’s some evidence for eating earlier in the evening: a 7.5-week trial in 39 adults with overweight or obesity found that ending meals at least three hours before sleep improved the overnight drop in the lower blood pressure number. It didn’t help with the other main outcome: how well the body responds to insulin, the hormone that controls blood sugar [16]. Both groups dimmed the lights three hours before bed, so the only difference was meal timing. This doesn’t mean there’s a universal dinner deadline.

Long-term health effects are harder to pin down. A 2025 study followed 19,831 adults for about 8 years and found that eating within less than 8 hours was linked to a higher risk of death from heart and circulatory disease compared to eating over 12 to 14 hours [17]. But eating hours were estimated from just two days of food recall, so there’s a lot of uncertainty about people’s real habits and whether the short window actually caused the higher risk.

Another analysis of the same survey and death records found the lowest risk of death from any cause was around 11 to 12 hours [18]. The authors used different rules and statistical methods. Both papers used overlapping data, and neither one proves what a safe eating window is.

In a newsletter in May 2025, I was too sure about preserving lean mass and left out the mortality finding that was already in my research notes. So here’s the full picture.

I don’t need a fixed eating window to manage my calories anymore. On training mornings, I drink my usual warm water, work out, and shower before breakfast. I usually have eggs or muesli with Greek yogurt, plus a big protein shake. On other mornings, I might write for about two hours before eating.

Reply and let me know what you hoped fasting would do for you. I read every message.

Stay healthy.

Andre

PS: If you know someone trying to pick a fasting schedule, feel free to share this with them. This is how this newsletter grows, and it’s the only way I want it to.

PPS: If someone forwarded this to you, you can sign up for free at

https://www.andreheeg.com

.

References

[1] Liu, D., Huang, Y., Huang, C., Yang, S., Wei, X., Zhang, P., Guo, D., Lin, J., Xu, B., Li, C., He, H., He, J., Liu, S., Shi, L., Xue, Y., Zhang, H. (2022). Calorie restriction with or without time-restricted eating in weight loss. New England Journal of Medicine, 386(16), 1495-1504. https://doi.org/10.1056/NEJMoa2114833

[2] Maruthur, N. M., et al. (2024). Effect of isocaloric, time-restricted eating on body weight in adults with obesity: A randomized controlled trial. Annals of Internal Medicine, 177(5), 549-558. https://doi.org/10.7326/M23-3132

[3] Catenacci, V. A., et al. (2025). The Effect of 4:3 Intermittent Fasting on Weight Loss at 12 Months. Annals of Internal Medicine, 178(5), 634-644. https://doi.org/10.7326/ANNALS-24-01631

[4] Semnani-Azad, Z., et al. (2025). Intermittent fasting strategies and their effects on body weight and other cardiometabolic risk factors: Systematic review and network meta-analysis of randomized clinical trials. BMJ, 389, e082007. https://doi.org/10.1136/bmj-2024-082007

[5] Nobel Assembly at Karolinska Institutet. (2016, October 3). The Nobel Prize in Physiology or Medicine 2016. https://www.nobelprize.org/prizes/medicine/2016/press-release/

[6] Pietrocola, F., et al. (2017). Autophagy, 13(3), 567-578.

[7] Bensalem, J., et al. (2025). The Journal of Physiology, 603, 3019-3032. https://doi.org/10.1113/JP287938

[8] Inverse. (2021, updated 2024). Stop trying to trigger autophagy. https://www.inverse.com/mind-body/stop-trying-to-trigger-autophagy

[9] Zero. (n.d.). Fast your way to autophagy. Accessed September 5, 2026. https://zerolongevity.com/blog/fast-your-way-to-autophagy/

[10] Fastic. (n.d.). Intermittent fasting app. Accessed September 5, 2026. https://fastic.com/en

[11] Centers for Disease Control and Prevention. (1998). Hyperthermia and dehydration-related deaths associated with intentional rapid weight loss in three collegiate wrestlers, North Carolina, Wisconsin, and Michigan, November-December 1997. MMWR Morbidity and Mortality Weekly Report, 47(6), 105-108.

[12] Moro, T., et al. (2021). Twelve months of time-restricted eating and resistance training improves inflammatory markers and cardiometabolic risk factors. Medicine & Science in Sports & Exercise. https://pmc.ncbi.nlm.nih.gov/articles/PMC10115489/

[13] Tinsley, G. M., et al. (2019). Time-restricted feeding plus resistance training in active females: A randomized trial. American Journal of Clinical Nutrition, 110(3), 628-640. https://doi.org/10.1093/ajcn/nqz126

[14] Bamberg, C., & Moreau, D. (2025). Psychological Bulletin, 151(9). https://doi.org/10.1037/bul0000492

[15] Elsworth, R. L., et al. (2023). The effect of intermittent fasting on appetite: A systematic review and meta-analysis. Nutrients, 15(11), 2604. https://doi.org/10.3390/nu15112604

[16] Grimaldi, D., et al. (2026). Arteriosclerosis, Thrombosis, and Vascular Biology, 46(4), e323355. https://pubmed.ncbi.nlm.nih.gov/41674465/

[17] Chen, M., et al. (2025). Diabetes & Metabolic Syndrome, 19(7), 103278. https://doi.org/10.1016/j.dsx.2025.103278

[18] Mao, Z., et al. (2025). Aging Cell, 24(11), e70230. https://doi.org/10.1111/acel.70230

On Saturday, researchers shared the results of the STAREE trial at a cardiology congress in Munich, and the full paper appeared in the New England Journal of Medicine the same day. In this study, 9,971 adults aged 70 and older, who did not have heart disease, diabetes, or dementia at the start, received either 40 mg of atorvastatin or a placebo.

The trial set out to answer two main questions. First, it tracked heart attacks, strokes, cardiac deaths, and stent procedures. After about 5.9 years, 6.0% of people taking the drug had these events, compared to 8.3% on placebo. That 30% difference means 2.3 fewer people out of every 100 had these problems. Second, the study looked at whether the drug helped people live longer without dementia or physical disability. Here, those outcomes hit 12.8% of the drug group and 13.6% on placebo, a small difference that could have happened by chance.

So what?

Statins are among the most thoroughly studied drugs in medicine. Results from 27 randomized trials show they help prevent major vascular events, even for people at low risk. Even in that low-risk group, every 1 mmol/L drop in LDL cholesterol prevents about 11 events per 1,000 people over five years. The researchers concluded that the benefits are much greater than any known risks. If you already take a statin, there is no reason to stop based on this new study.

The real question is what benefit you personally might get. In Munich, that 2.3 in 100 came from adults with an average age of 74. In March, new US guidelines made 21.5 million more people eligible for statins. These people are younger and have a lower risk, with an average 3.1% risk over ten years. For them, the same 30% reduction means even fewer people benefit, but this is not always made clear. In Europe, the SCORE2 system is used, and the math works out the same.

The STAREE trial does not give information for people who are 50 years old. All participants were at least 70, and anyone with heart disease, diabetes, or dementia was excluded. So, you need to find out your own risk numbers.

Now what?

• If you already take a statin, do not change your prescription until you talk with your doctor. Make sure to mention any symptoms or concerns at that visit.

• Ask your doctor for your current risk estimate. In the US, learn about PREVENT and its 10-year and 30-year risk numbers. In Europe, ask which SCORE2 or SCORE2-OP estimate applies to you.

• Review your ApoB and your one-time Lp(a) test result with your doctor. Try to keep ApoB below 80 mg/dL, or below 65 if you already have disease or a strong family history. Ask if a CAC score could change your risk category.

• Ask your doctor this specific question: “With this dose, how many percentage points will my risk go down over the years I am likely to take it?”

• At the same visit, ask about possible downsides. Serious side effects happened at the same rate in both groups, 2.7%. However, muscle, liver, and blood sugar problems were more common in people taking the drug.

You can find out your own risk number. Go and get it.

Stay healthy.

Andre

I started in my home gym with just the empty bar, which already felt heavier than normal. A weight I usually lift without thinking. Now the bar was 60 kilograms. Ten reps at that weight are usually just a warm-up for me. I know my body and what it can handle, so this should have been easy.

At 60 kilograms, I immediately felt that something was off.

I felt weak and my muscles just wouldn’t work the way they normally do. I tried jumping to wake myself up, slapped my face, and turned up the music, hoping for a burst of energy.

By rep 5, I had to stop and reset.

“This isn’t a warm-up.”

If this had only happened once, I would have just called it a bad session. But it kept going for a week or two.

When I say I did everything ‘right,’ I mean everything my career had taught me to do. But my body needed something else. I was doing everything ‘right’ except for the one thing I never thought of as work.

When discipline stops paying

I believed anyone could do it if they wanted it badly enough and went after it.

Discipline was always at the center of what I believed. If something was tough, I just pushed through. When my days got busy, I slept less. If I had 30 free minutes, I filled them with something productive. I was proud that I never just sat on the couch.

I also thought the usual rules about rest and recovery didn’t apply to me.

“I’m the one who’s built differently.”

I believed I could manage on just 4 or 5 hours of sleep. My favorite saying was, “I sleep when I’m dead.” Not giving my best felt like wasting time. I was proud of that attitude, and it helped me for much of my career. Whenever I felt tired or unfocused, I just pushed myself harder.

A 2022 meta-analysis pooled 227 outcomes from 77 participant pools involving 959 participants. The review compared sleep duration at or below 6 hours with duration above 6 hours. The pooled reduction in exercise performance was 7.56% (95% CI, 3.13% to 11.9% lower). For maximal-strength tests, 66 outcomes from 25 participant pools involving 289 participants produced a pooled reduction of 2.85% (95% CI, 1.23% to 4.47% lower) [1].

The doctor’s take: The averages show that losing sleep can hurt exercise performance, but they don’t really explain what happened to me. Most of the study participants were men, and the results were all over the place. The review didn’t include people with ongoing sleep loss, sleep disorders, or shift work, and my struggles lasted a week or two. The strength results were from maximum-effort tests, but I was just doing warm-up reps. So, I see sleep loss as one possible reason, but this study doesn’t give me a clear answer.

The gap between feeling and function

In 2003, researchers put healthy adults aged 21 to 38 through 2 weeks of restricted sleep. Researchers assigned 35 people to 4, 6, or 8 hours in bed each night. The 4-hour and 6-hour groups developed cumulative, dose-dependent losses on tests of vigilance, working memory and cognitive throughput compared with the 8-hour group [2].

As a group, people felt sleepier at first, but that feeling didn’t change much after that. Their actual performance kept getting worse. The researchers said people didn’t really notice how much they were slipping. The study didn’t prove that those who did the worst were the least aware.

I’ve noticed this mentally too. Sometimes I read the same paragraph four times and still can’t remember it. I open a presentation and can’t finish a single slide without starting over. At home, I feel it emotionally. My patience runs thin, and I overreact to small problems with my kids.

The doctor’s take: The study measured time in bed, not actual sleep, and only six women were included out of 48 people. It was done in a lab setting. The finding about awareness was seen in the group as a whole, not in individuals. If you keep struggling with a simple task, notice it before judging yourself. A tough squat, a blank slide, or a short temper can have many causes. I treat these changes as signals. If your usual performance drops, don’t just push harder without asking why.

I kept driving

My wife was asleep next to me during an evening drive on a weekend trip in Germany. The week before, I hadn’t slept well, ate at odd times, and drank too much coffee.

I fought off sleep for about an hour. I opened the window, had another energy drink, and turned up the music. Still, I kept driving.

I do not remember falling asleep.

I remember a loud rattling and the car shaking. When I looked up, we were off the road in the grass. I think I lost about 10 to 20 seconds, but I can’t be sure. I was probably driving around 130 to 140 kilometers per hour. Luckily, no other cars were nearby, and the only damage was a few scratches that could be fixed.

I pulled over at the next parking area, slept for a while, and then kept driving. I don’t see that nap as proof that the rest of the drive was safe.

Looking back, I know I was irresponsible. I put my life and my wife’s life at risk. I can’t let that happen again.

For adults aged 18 to 60, a joint sleep-medicine consensus recommends 7 or more hours of sleep each night on a regular basis. The same statement associates regular short sleep with impaired performance, more errors, and greater risk of accidents [3].

Looking for a number

I also took a salivary cortisol test while searching for a number that might explain what was happening.

A systematic review of 190 studies found insufficient evidence to establish cortisol secretion patterns in burnout, partly because burnout was measured inconsistently across studies [4]. A separate review by 2 endocrinologists covered 58 heterogeneous studies and found no proof of the specific condition called adrenal fatigue. In 16 of 26 studies of the daily salivary cortisol rhythm, fatigued patients did not differ from controls [5].

The doctor’s take: These reviews cover different topics. Research on burnout hasn’t found a clear cortisol pattern for diagnosis. Adrenal fatigue is a separate idea, and not all 58 studies tested it directly. Neither review says burnout or exhaustion aren’t real. My test is just one part of my search, even though it didn’t give me an answer.

You can now buy a cortisol curve as a stress score. Saliva cortisol is a real test, and doctors use it to screen for Cushing’s syndrome, so the lab work is sound. Those kits skip how much your own curve moves from one day to the next. A meta-analysis across 11 studies and 3,307 people found agreement between one day and the next running from zero to moderate, and the morning cortisol rise that many kits sell scored 0.29, which the authors call poor [6]. If someone sells you a cortisol score, ask how many days they measured.

What I can move

From my experience, and in most work environments, it’s usually only possible to adjust your workload a little. I’ve found it’s easier to make changes to recovery, though that gets harder when demands go up or when things like caregiving, shift work, or money get in the way.

A meta-analysis found that greater job demands were associated with less psychological detachment across 60 effect sets involving 28,507 employees. Psychological detachment is the concept of your mind leaving your work, similar to your body. In 23 effect sets involving 7,007 employees, greater detachment was associated with less exhaustion [7].

The doctor’s take: Job demands are more than just workload. The studies were very different, and the results weren’t always clear. Most of the data came from self-reports and single points in time, so we can’t say for sure that detachment lowers exhaustion. In my own life, I can’t usually get rid of work, but I can often save a bit of time in the evening, on weekends, or during the day.

One morning in our hallway in Berlin, while the kids got ready for school, I sat on a small stool to put on my shoes. My back pain had been getting worse for weeks. I kept avoiding my socks all morning because bending over hurt. I tried to make my request for help sound casual and blamed it on being in a hurry.

“Can you quickly help me?”

My wife looked at me. She had reason to check because I sometimes play tricks on her.

“Really? Are you serious? You can do this on your own, right?”

Soon I needed that help regularly.

Recovery belongs in the equation

I published The Upward ARC in May 2025, where I organized good habits into three categories: Activate, Recover, and Capacity. Looking back, I would write it differently now.

Activate means deliberate load on a system. A training session is load. So are sustained concentration, emotional control, and the repeated decisions of a senior role.

Recover is the time the system has to respond to that load.

Capacity is the output that follows.

Now, I see these three categories as a loop and focus more on what happens after the effort. Finishing a workout or a document is just the input. The real result is what I can do after my body or mind has had time to recover. If recovery time keeps shrinking, the same effort starts to feel harder.

This is the approach I use in my own life. There isn’t proof of one universal biological loop for strength, thinking, and emotions. Sports medicine gives us the clearest example. Experts from the European College of Sport Science and the American College of Sports Medicine agree that good athletic training needs enough challenge, but not too much without enough recovery. If you build up too much stress, from training or life, it can take days or even weeks to recover [8].

What I’ve learned at work is that load and recovery need to be balanced. If demands keep coming and recovery isn’t enough, pushing harder just adds more strain. Eventually, your capacity levels off and then drops.

I break down capacity into three areas: physical, cognitive, and social-emotional. Physical capacity is when the bar suddenly feels heavy. Cognitive capacity is when you can’t remember a paragraph. Social-emotional capacity is when you can’t find your usual patience. This is the framework I use in my work.

The doctor’s take: If my usual performance drops for several days, I focus on recovery before pushing myself harder. I ask if I’ve given myself enough time to recover from what I’ve already done. There’s a time component to this. Sometimes it makes sense to push through and take on more. Then you recover and bounce back. But it doesn’t work to push for long periods without a break.

This changes how I read a recent edition about choosing the few habits that survive a hard week: https://www.andreheeg.com/archive/you-already-know-what-to-do-that/

Try this today

• Set a minimum amount of sleep and stick to it. Experts recommend at least seven hours a night for adults aged 18 to 60 [3]. This is the minimum for good health, but seven hours doesn’t always mean you’ll feel fully rested.

• When I have to choose, I pick sleep. If it’s between a 5:30 workout or an extra hour in bed, I choose the sleep. That’s what I do, even though no study has directly compared these two options.

• Take short breaks during your workday. I like to go for a walk or do some breathing exercises. A meta-analysis of 22 samples found that breaks of 10 minutes or less gave a small boost in how people felt, but didn’t make a big difference in performance. Only less demanding tasks showed a clear benefit, and longer breaks helped more [9].

• Stay in touch with people who aren’t connected to your work. When I’m in Berlin, or when my travel schedule allows, I try to meet a friend and talk about things outside of my job. Stronger social relationships were linked to a 50% higher chance of survival in 148 studies with over 300,000 people [10]. How social relationships are defined affects the size of this link. The study doesn’t prove that social contact helps with recovery, but that’s how I see it, and it’s why I keep up this habit.

• Pay attention to slow changes over time. I watch for shifts in my physical, mental, and emotional capacity during everyday tasks, like how a warm-up feels, if I have to reread a document, or how I react to small family issues. This is what I do, without relying on any device or diagnosis.

Recovery still isn’t easy for me. I usually manage to get enough sleep now, but it’s easy to let social connections slide. I often get caught up in work and realize late in the day that I haven’t eaten properly or had enough water.

Effort has paid off for me most of my life, and I still value it. Now, I try to use some of that discipline for sleep, breaks, and spending time with people outside of work.

Which type of capacity drops first for you: physical, cognitive, or social-emotional? Reply with just one word. I read every response.

Stay healthy.

Andre

PS: If you know someone who always tries to fight exhaustion by working harder, please forward this edition to them. That’s how this newsletter grows, and it’s the only way I want it to.

PPS: If a friend sent you this, you can sign up for Under Load, my Sunday edition, at

https://www.andreheeg.com

References

[1] Craven, J., McCartney, D., Desbrow, B., Sabapathy, S., Bellinger, P., Roberts, L., & Irwin, C. (2022). Effects of acute sleep loss on physical performance: A systematic and meta-analytical review. Sports Medicine, 52(11), 2669-2690.

[2] Van Dongen, H. P. A., Maislin, G., Mullington, J. M., & Dinges, D. F. (2003). The cumulative cost of additional wakefulness: Dose-response effects on neurobehavioral functions and sleep physiology from chronic sleep restriction and total sleep deprivation. Sleep, 26(2), 117-126.

[3] Watson, N. F., Badr, M. S., Belenky, G., Bliwise, D. L., Buxton, O. M., Buysse, D., Dinges, D. F., Gangwisch, J., Grandner, M. A., Kushida, C., Malhotra, R. K., Martin, J. L., Patel, S. R., Quan, S. F., & Tasali, E. (2015). Recommended amount of sleep for a healthy adult: A joint consensus statement of the American Academy of Sleep Medicine and Sleep Research Society. Journal of Clinical Sleep Medicine, 11(6), 591-592.

[4] Rothe, N., Steffen, J., Penz, M., Kirschbaum, C., & Walther, A. (2020). Examination of peripheral basal and reactive cortisol levels in major depressive disorder and the burnout syndrome: A systematic review. Neuroscience & Biobehavioral Reviews, 114, 232-270.

[5] Cadegiani, F. A., & Kater, C. E. (2016). Adrenal fatigue does not exist: A systematic review. BMC Endocrine Disorders, 16, 48.

[6] Norton, S. A., Baranger, D. A. A., Young, E. S., Voss, M., Hansen, I., Bondy, E., Rodrigues, M., Paul, S. E., Edershile, E., Hill, P. L., Oltmanns, T. F., Simpson, J., & Bogdan, R. (2023). Reliability of diurnal salivary cortisol metrics: A meta-analysis and investigation in two independent samples. Comprehensive Psychoneuroendocrinology, 16, 100191.

[7] Wendsche, J., & Lohmann-Haislah, A. (2017). A meta-analysis on antecedents and outcomes of detachment from work. Frontiers in Psychology, 7, 2072.

[8] Meeusen, R., Duclos, M., Foster, C., Fry, A., Gleeson, M., Nieman, D., Raglin, J., Rietjens, G., Steinacker, J., & Urhausen, A. (2013). Prevention, diagnosis, and treatment of the overtraining syndrome: Joint consensus statement of the European College of Sport Science and the American College of Sports Medicine. Medicine & Science in Sports & Exercise, 45(1), 186-205.

[9] Albulescu, P., Macsinga, I., Rusu, A., Sulea, C., Bodnaru, A., & Tulbure, B. T. (2022). “Give me a break!” A systematic review and meta-analysis on the efficacy of micro-breaks for increasing well-being and performance. PLOS ONE, 17(8), e0272460.

[10] Holt-Lunstad, J., Smith, T. B., & Layton, J. B. (2010). Social relationships and mortality risk: A meta-analytic review. PLOS Medicine, 7(7), e1000316.

What?

Megan Ritson and colleagues looked at data from 32 studies, covering more than 100 million people. Of these, 19 studies gave 24 estimates about cannabis. When all the data was combined, cannabis was linked to 37% higher odds of stroke, cocaine to 96%, and amphetamines to 122%. In their main analysis, opioids did not show a significant link overall.

The cannabis studies had very mixed results. On the standard measure of how much studies disagree with each other, they came out at 99%, which is about as inconsistent as a meta-analysis can get. The authors found that smaller studies influenced the results, and after adjusting for this, the cannabis figure dropped from 37% to 12%. Only 14 of the 32 studies clearly showed that drug use happened before the stroke.

So what?

The study does not show how the risk changes with different doses or how often someone uses cannabis. Its strongest evidence is about cannabis use disorder, which means problematic or dependent use. This is very different from using cannabis occasionally, but the paper also cannot estimate the risk for people who use it only sometimes.

The genetic analysis suggests that cannabis use disorder might cause stroke, but it focused on genetic risk for cannabis use disorder, not just general cannabis use. For people under 55, the figure was 14% higher odds, but this is similar to the result for all ages. The authors say there was no significant difference by age.

For me, this study is a reminder to watch for patterns. If you find yourself using cannabis every night to help you sleep, it’s worth paying attention. In the 2024 National Health Interview Survey of 31,509 adults, 3.7% said they used marijuana or CBD most days or every day for sleep. A National Sleep Foundation survey of 1,367 adults found that current users still slept worse than nonusers, though it didn’t show whether cannabis helped. A 2025 review looked at 18 sleep-lab studies, and in the 9 that could be combined, there was no consistent change in sleep duration, how long it took to fall asleep, how much of the night was spent asleep, or sleep stages.

Now what?

Five questions are more helpful than any number this study could provide.

• How many nights out of the last 30?

• Has the dose gone up?

• Can you sleep without it?

• Have you tried to cut down and failed?

• Are you carrying on despite worse sleep, daytime fog or something else?

Then three things worth doing regardless of your answers.

• If you have ongoing insomnia, address it directly. CBT-I is the best first treatment, even before trying medication. Two key parts of CBT-I are waking up at the same time every day and getting out of bed if you can’t sleep, but the full program includes more steps.

• Check your average blood pressure with proper home readings. No matter how cannabis fits in, blood pressure is the main stroke risk factor you can control.

• If you decide to take a break, expect the first few days to be the hardest, and remember that withdrawal can last several weeks. In a national sample of people who used cannabis at least three times a week, 12% had withdrawal syndrome, and 68% of those had trouble sleeping. This is a self-test, not a result from the stroke study.

If you use cannabis just once a month, this study cannot tell you your risk. The genetic evidence is about cannabis use disorder, and the other studies did not track use often enough to set a safe limit.

I wrote in detail about sleep problems in July, including why most effective solutions are not for sale. You can read it here: [archive URL needed]

This paper is a warning about problematic cannabis use. It’s more helpful to ask yourself the five questions than to focus on a number the study never actually tested.

Stay healthy.

Andre

The healthcare company filled the booth with its products and set up a section for its over-the-counter continuous glucose monitor (CGM). Staff gave out little treats and packets of electrolyte powder.

I had just left their CES panel, “Tracking Your Body’s Signals for Better Health,” at the Venetian Expo. Tunde Oyeneyin talked about using glucose data for cardio and preparation. I know her from Peloton and like her as a personality. Alexis Ohanian, Reddit’s co-founder, brought in a tech and fatherhood perspective, which I find interesting. He also appeared in the product’s “Spike Sessions” campaign, which is worth mentioning when considering his role on the company’s stage [1][2].

After 3 years of doubt, I wondered whether I should try one and later speak from experience.

The booth was big. My estimate is six figures, probably more. I spoke with someone I remember as a brand manager or salesperson. They kept explaining how eating order affects glucose, and how levels rise after eating carbs. I kept asking what a healthy person should do after a normal increase.

I never got an answer I could use. I left with a few samples, but not a glucose monitor. I still haven’t tried one.

My doctor’s take begins with me

That’s a fair point. I’m judging a device I haven’t tried myself.

I’m a physician with medical and dental degrees, but I don’t specialize in endocrinology or diabetes. I look at health devices like any other treatment: identify the problem, decide what action to take based on the result, and see if that action improves health.

I use the same approach for myself. Twice a year, I check my fasting glucose and HbA1c, which shows long-term glucose levels. My results are 92 mg/dL (about 5.1 mmol/L) and 4.9%.

I also take valsartan with hydrochlorothiazide for high blood pressure, which is well controlled. I take my medication and check my blood pressure regularly because there’s a clear target, and lowering it reduces health risks.

Hydrochlorothiazide belongs to a family of blood-pressure drugs called thiazides. Across 95 randomized trials in which treatment was assigned by chance, these drugs raised fasting glucose by 3.6 mg/dL on average, or 2.7 mg/dL in trials lasting at least 6 months. The authors called the class effect too small to change care [3]. It cannot predict my result without the drug.

Blood-pressure treatment also counts as 1 of the 5 markers used to define metabolic syndrome, a cluster of linked health risks. The diagnosis requires 3 markers. My treated hypertension is a managed cardiovascular risk factor; by itself, it does not meet that definition [4].

Where the evidence holds

For the right patient with diabetes, continuous glucose monitoring earns its place.

A review published in JAMA Internal Medicine on 3 August 2026 summarized randomized evidence in type 2 diabetes. Average HbA1c fell by about 0.3 percentage points compared with finger-prick checks or usual care, and some patients gained more. Much of that evidence came from people taking insulin or other glucose-lowering drugs [5].

This was a narrative review, meaning the authors chose and explained existing research without the strict process of a systematic review. Published at the journal’s initiative, it found only limited and indirect support for CGM in people with type 2 diabetes not taking glucose-lowering treatment, or with prediabetes or obesity. No CGM-manufacturer conflict was disclosed.

Prediabetes is a different case, since the evidence is more promising there. Here, I’m focusing on healthy adults without symptoms.

Minna Johansson set the boundary in a university press statement: “This technology is tremendously valuable for certain groups of patients. But it is increasingly being used by groups where we simply do not know whether it provides any benefit at all—or if it could even be harmful” [6]. The review didn’t measure a harm rate. The authors suggested using CGM only when a specific patient problem gives the readings a purpose. This is not a clinical guideline.

The FDA cleared Lingo for over-the-counter sale to adults aged 18 or older who do not use insulin. This includes some people with diabetes. Its screen covers 55 to 200 mg/dL, and the agency says users should consult a qualified health professional before taking medical action based on the output [7].

Even precise numbers can be misleading

Hutchins and colleagues ran a randomized crossover study in 15 healthy adults. Each person completed the same set of meal tests, with the order chosen by chance, so the researchers could compare each person with themselves.

The continuous monitor read 0.9 mmol/L, about 16 mg/dL, higher than a finger-prick test both before and after meals. For one smoothie, the monitor gave a glycemic index of 69 and the finger-prick method gave 53. Glycemic index is a score for how strongly a food raises glucose [8].

Those estimates had wide confidence intervals. A confidence interval is the range that still fits the data. The monitor’s range was 48 to 99, while the finger-prick range was 40 to 69. These ranges overlap a lot.

The p-value was .05. A p-value asks how often a difference this big could happen by chance if both methods worked the same. Here, it was about 5 times in 100, which is the usual cutoff researchers use. This example comes from one smoothie and 15 people, not a general error rate.

After adjusting for each person’s starting point, the monitor still showed about twice as much time above 140 mg/dL compared to the finger-prick method. The p-value was below .01, meaning a gap this large would happen less than once in 100 times if there was no real difference. They measured time above 140, not the actual glucose concentration.

Innocent Drinks funded the study with an unrestricted grant and provided the test products. “Unrestricted” means the company didn’t control how the study was run. The authors also disclosed connections to ZOE, PepsiCo, and the European Fruit Juice Association.

Then 18 CGM experts looked at 20 reports from adults without diabetes and decided whether each person needed medical follow-up. The researchers had deliberately chosen difficult reports. Dexcom supplied discounted sensors, and several authors had ties to the manufacturer [9].

Fleiss kappa measures how much a group agrees beyond what chance alone would produce. A score of 0 means chance-level agreement; 1 means perfect agreement. These experts scored 0.36, which the authors called low. All 18 gave the same answer on only 3 of the 20 reports. They all wanted follow-up for 2 and all declined it for 1. This measured agreement in a small selected set. It did not test whether their decisions were medically correct.

One rough pattern appeared. When more than 2 out of every 100 readings were above 180 mg/dL, between 56% and 100% of the experts recommended follow-up, depending on the report. Simply put, the same cutoff convinced just over half of them in some cases and all of them in others. The study didn’t prove that 2% was the right alarm line. I think this number comes from diabetes care. The authors said there are no guidelines for interpreting these reports in people without diabetes. Diabetes care has its own guidelines.

My doctor’s take after the evidence

This fits into the Activate part of the Upward ARC, which focuses on food and movement. It also relates to Capacity, since our attention is limited. Every new number asks you to look, interpret, and decide what to do.

Before buying a monitor, a healthy person should think about what reading would make them change their behavior.

Try this today

• Write down the exact number that would make you change your actions. Add what you would do next and what result you expect. If you can’t fill the page, that tells you something.

• If you have diabetes, prediabetes, symptoms, pregnancy, medication concerns, or another metabolic risk, take the question to a clinician. This newsletter doesn’t cover you.

• Try the habit without tracking it on a graph. Eat protein before carbs if you like. Take a 10- or 20-minute walk after eating. See if you can keep it up.

• Consider what the experiment costs, both in money and attention. Lingo launched at $89 for two 14-day sensors in the US. On 21 August 2026, its US 4-week subscription showed an $89 standard price, and Boots in the UK listed two sensors for £118 [10][11]. Decide before you start when you’ll stop.

The unused patches

About a year ago, I noticed an opened FreeStyle Libre package next to a monitor at the office. A blister pack of patches was still sealed. Since the desks were shared, I didn’t know whose it was. Later that day, a colleague told me they saw an influencer wearing one and bought it with a discount code. They showed me the sensor on their arm.

They learned that eating protein before carbohydrates seemed to flatten the curve. A 10- or 20-minute walk after eating had a similar effect. Fruit or something sweet made glucose rise and then fall.

I could have told them all of that without a sensor.

A few weeks later, I asked if they were still using it. They had stopped. I inferred that it had been an expensive way to learn basic lessons. They never said why they quit.

Normal is broader than it seems

The Framingham study followed 560 normoglycemic adults. That simply means their standard blood tests placed them in the normal glucose range [12].

Even so, their readings sat between 140 and 180 for almost 3 hours a day, then above 180 for another 19 minutes. Total time above 140 averaged roughly 3.3 hours. This was a group average, so it doesn’t predict one person’s day. Participants averaged 58.8 years old and had an average body mass index of 26.5, which indicates overweight. The group was 93.2% non-Hispanic White, and Dexcom supplied discounted sensors.

A second study followed 153 healthy, non-obese people aged 7 to 80 [13]. The sample averaged 31 years old. Average glucose was 98 to 99 mg/dL below age 60 and 104 at 60 or older. The median person (the middle value after ranking) spent 96% of the day between 70 and 140. The interquartile range was 93% to 98%, meaning the middle half of participants fell between those values. The sample was 93% White, and an author disclosed ties to Dexcom and Sanofi.

I think the difference comes down to age and who was in each study. The younger group didn’t include people with obesity, while the Framingham study looked at an older community group. Neither paper tested this, so this is just my opinion. Both studies show that healthy glucose levels can vary. Seeing a colored line can make normal changes look like a problem.

Curiosity still needs a purpose

In PREDICT 1, 1,002 generally healthy UK adults ate identical standard meals. Their population coefficient of variation was 68% [14]. This compares the spread of responses with the average; 68% signals wide variation. It is neither the share of people who reacted differently nor a treatment effect. Several authors worked for or consulted with ZOE.

A 2026 systematic review used preset rules to find and assess 23 studies [15]. It found signs of benefit in prediabetes and no appreciable improvement in healthy groups. Only 5 studies could be combined numerically. Most randomized studies lasted 12 weeks or less and paired the sensor with education or coaching, leaving its separate effect unclear.

Another review covered 25 randomized behavior-change trials [16]. Only 3 involved people without diabetes, all with obesity, and every trial added other support. Eight supplied weight data. The combined result was 0.7 kg less, with P = .066. If the true effect were zero, a result this large could appear by chance about 6.6 times in 100. It missed the usual cutoff and was not statistically significant. The analysis could not reliably separate a small loss from random variation, though it didn’t prove zero effect. Eleven trials reported CGM-industry conflicts, which proves neither funding nor bias.

When I visited the booth, I was open to trying a CGM. But after talking with them, I kept coming back to the same question: what should you do after seeing a normal rise in glucose from eating a banana?

I still don’t have a good answer for healthy people without symptoms. My first thought remains: for this group, a CGM is mostly a waste of money.

A monitor might encourage you to take a walk, but it can also turn normal body changes into warnings that even experts can’t interpret. I already have enough information to decide when to take a walk.

I took the electrolyte powder and left the monitor behind.

If you’ve worn a CGM without a diagnosis, what decisions are you still making differently six months later? Reply and tell me exactly what’s changed. I want to know if I’m missing something in my conclusion.

Stay healthy.

Andre

PS: This argument is for healthy, asymptomatic adults. If you know someone who uses a CGM, please forward this to them. That’s how this newsletter grows, and it’s the only way I want it to.

PPS: If someone forwarded this to you, you can get Under Load, my Sunday edition, here:

https://www.andreheeg.com

References

[1] Consumer Technology Association. (2025, January 7). Tracking your body’s signals for better health, presented by Abbott [Conference session]. CES 2025. https://www.ces.tech/videos/tracking-your-body-s-signals-for-better-health-presented-by-abbott/

[2] RQ Agency. (n.d.). Lingo. https://rqagency.com/work/lingo

[3] Hall, J. J., Eurich, D. T., Nagy, D., Tjosvold, L., & Gamble, J.-M. (2020). Thiazide diuretic-induced change in fasting plasma glucose: A meta-analysis of randomized clinical trials. Journal of General Internal Medicine, 35(6), 1849-1860. https://doi.org/10.1007/s11606-020-05731-3

[4] Alberti, K. G. M. M., Eckel, R. H., Grundy, S. M., Zimmet, P. Z., Cleeman, J. I., Donato, K. A., Fruchart, J.-C., James, W. P. T., Loria, C. M., & Smith, S. C., Jr. (2009). Harmonizing the metabolic syndrome: A joint interim statement of the International Diabetes Federation Task Force on Epidemiology and Prevention; National Heart, Lung, and Blood Institute; American Heart Association; World Heart Federation; International Atherosclerosis Society; and International Association for the Study of Obesity. Circulation, 120(16), 1640-1645. https://doi.org/10.1161/CIRCULATIONAHA.109.192644

[5] Dower, J. A., Johansson, M., Camp, A. W., Montori, V. M., & Lipska, K. J. (2026). Continuous glucose monitoring in type 2 diabetes and beyond: A review. JAMA Internal Medicine. Advance online publication. https://doi.org/10.1001/jamainternmed.2026.2772

[6] University of Gothenburg. (2026, August 3). No evidence that continuous glucose monitors improve health in people without diabetes [Press release]. https://www.gu.se/en/news/no-evidence-that-continuous-glucose-monitors-improve-health-in-people-without-diabetes

[7] U.S. Food and Drug Administration. (2024, May 29). 510(k) premarket notification K233655: Lingo Glucose System. https://www.accessdata.fda.gov/cdrh_docs/pdf23/K233655.pdf

[8] Hutchins, K., Betts, J., Thompson, D., Hengist, A., & Gonzalez, J. (2025). Continuous glucose monitor overestimates glycemia, with the magnitude of bias varying by postprandial test and individual: A randomized crossover trial. American Journal of Clinical Nutrition, 121(5), 1025-1034. https://doi.org/10.1016/j.ajcnut.2025.02.024

[9] Spartano, N. L., Prescott, B., Walker, M. E., et al. (2025). Expert clinical interpretation of continuous glucose monitor reports from individuals without diabetes. Journal of Diabetes Science and Technology, 20(3), 727-735. https://doi.org/10.1177/19322968251315171

[10] Abbott. (2024, September 5). Abbott’s Lingo continuous glucose monitor for health and wellness now available in the U.S. https://abbott.mediaroom.com/2024-09-05-Abbotts-Lingo-TM-Continuous-Glucose-Monitor-for-Health-and-Wellness-Now-Available-in-the-U-S

[11] Boots. (2026). Lingo continuous glucose monitor bundle. Retrieved August 21, 2026, from https://www.boots.com/lingo-continuous-glucose-monitor-bundle-10390678

[12] Spartano, N. L., Sultana, N., Lin, H., et al. (2025). Defining continuous glucose monitor time in range in a large, community-based cohort without diabetes. The Journal of Clinical Endocrinology & Metabolism, 110(4), 1128-1134. https://doi.org/10.1210/clinem/dgae626

[13] Shah, V. N., DuBose, S. N., Li, Z., et al. (2019). Continuous glucose monitoring profiles in healthy nondiabetic participants: A multicenter prospective study. The Journal of Clinical Endocrinology & Metabolism, 104(10), 4356-4364. https://doi.org/10.1210/jc.2018-02763

[14] Berry, S. E., et al. (2020). Human postprandial responses to food and potential for precision nutrition. Nature Medicine, 26, 964-973. https://doi.org/10.1038/s41591-020-0934-0

[15] Liao, X., Li, Y., Tang, S., Xiao, Y., Yu, X., Huang, R., & Zhong, T. (2026). Continuous glucose monitoring in non-diabetic populations: A systematic review of observational and interventional studies with meta-analysis. European Journal of Medical Research, 31, Article 397. https://doi.org/10.1186/s40001-026-03920-0

[16] Richardson, K. M., Jospe, M. R., Bohlen, L. C., et al. (2024). The efficacy of using continuous glucose monitoring as a behaviour change tool in populations with and without diabetes: A systematic review and meta-analysis of randomised controlled trials. International Journal of Behavioral Nutrition and Physical Activity, 21, Article 145. https://doi.org/10.1186/s12966-024-01692-6

What?

Let’s start with the most reliable method. A USC-led study published in npj Aging on July 20 tested the five most popular epigenetic clocks on 3,227 adults from the Health and Retirement Study. These clocks, Horvath, Hannum, PhenoAge, GrimAge, and DunedinPACE, did not share a single gene in common. The authors said there were “more unique than common biological processes.”

These clocks can also give inconsistent results. A 2022 study in Nature Aging found that technical noise alone could make six of these clocks show up to a nine-year difference when testing the same sample twice. Newer versions have reduced this gap to about 1.5 years, so there is a fix. Still, most reports don’t say which version was used for your result.

Consumer options are even less accurate. EGYM gym machines use four fitness tests: strength, cardio, metabolism, and flexibility. WHOOP figures out your age from months of sleep, training, and recovery data. Garmin mostly uses your VO2max. This means the same person could get three different ages from three devices.

So what?

None of these tools truly measure aging. They look at your fitness and habits, then turn those results into years, since that’s a number people understand.

I think that’s okay. If a simple number gets someone to go to the gym on a Tuesday, that’s more useful than a perfect measurement no one pays attention to. Treat it like a game. If your watch pushes you to work out a fourth time this week, it’s working.

The problem is when doctors present a vendor’s score as if it’s a real lab result. Then the suggestion becomes a claim. Most people can’t tell the difference. That’s why credentials matter, and using them to support an unproven number isn’t a good idea.

Now what?

• See your ‘age’ score as a tool to track your habits, not as something for your official health record.

• Focus on the numbers behind the score: your VO2max (in ml/kg/min), strength, waist size in centimeters, and blood pressure. Each of these can predict health outcomes by itself.

• Only compare your results to your own past results, using the same device and the same conditions. Numbers from different brands can’t be compared.

• If you get a score, ask your provider two questions: Has this score been tested against illness or death in people outside their database? And which version of the clock are they using?

• If a gym blood pressure cuff shows 140/90 or higher, check your blood pressure at home over several days. The 2024 European Society of Cardiology guidelines recommend out-of-office readings before making a diagnosis.

I made a similar point in July about the supplements in your cupboard. You can read more in The Doctor’s Edit on Your Longevity Drawer (https://www.andreheeg.com/archive/the-doctors-edit-on-your-longevity-drawer).

Let the number motivate you to go to the gym. That’s its only purpose.

Stay healthy.

Andre

The result was a pale brown drink with a foamy, shiny layer that caught the morning light. I drank it at the counter before anyone else woke up, and I felt great about it.

I have both a medical and a dental degree. Even so, I ended up drinking butter for breakfast after hearing someone on a podcast explain the science. It made sense to me at the time.

These things always seem to make sense at first. That’s the real problem.

My butter phase lasted about two years. Then I switched to MCT oil, which cost almost as much as the whiskey on the shelf. After that came coconut oil, then ghee, which I thought was an upgrade. Now I use olive oil. Each choice felt reasonable at the time.

Each phase had its own expert, a scientific reason, and a type of fat to avoid. The latest trend has the most talked-about villain so far.

Before all of this, there was a hallway. After three training sessions that day, we would sit on the floor outside our rooms, leaning against the wall. On the youth national team, we shared rooms in a long corridor lined with doors. You could recognize another wrestler from across the room without saying anything. It was the ears that gave us away.

In May, Robert Saleh, in his first year coaching the Tennessee Titans, told reporters that removing every seed oil from the facility had been one of the first changes he made, part of an overhaul of how the team eats [1]. Canola and soybean oil, out of an NFL building.

Recently, more executives have asked me about seed oils than ever before. So I read everything I could find on the topic, including both sides and even the arguments I expected to disagree with.

The biology he describes is real

Paul Saladino is one of the most-followed voices arguing that seed oils are doing serious damage. He’s a physician, and he writes this on his own site: “we STORE these polyunsaturated fats in our cell membranes and mitochondrial membranes” [2].

He’s right about that.

Linoleic acid, the main omega-6 fat in conventional sunflower, corn, soybean, and canola oils, gets built into cell membranes and body fat. A review of 37 studies found that its share of American adipose fatty acids rose from 9.1% in 1959 to 21.5% in 2008 [3]. The review estimated a half-life in fat tissue of about 680 days.

Polyunsaturated fats oxidize more readily than saturated fats. In a laboratory study, peroxidized linoleic acid damaged isolated DNA [4].

In the most recent American dietary survey, foods coded as fats supplied 8% to 13% of people’s linoleic acid. Grains supplied 22% to 35%, meat 15% to 25% [5]. Those are categories of reported food, so oil baked into bread still counts as grain. The survey can’t isolate what came from a bottle. The bottle is the visible part of exposure spread across many foods.

Each of my phases started with a solid scientific explanation. Medium-chain fats are processed differently. Clarified butter removes milk solids. Now, I always ask a practical question: has anyone actually measured what happens to people who eat this?

Someone decided to test it

Saladino’s sharpest claim is about DNA. His words, as written: excess linoleic acid makes fat cells release free fats, and “These free fats induce insulin resistance in the peripheral muscles, causing inflammation and DNA damage” [6].

In 2003, the same group went looking in people. Thirty volunteers across three arms for six weeks, one taking 15 grams of linoleic acid a day against a palmitic acid control, measuring oxidative DNA damage in white blood cells. In the linoleic acid arm, the damage rose 13% from where it started and finished 23% below the control group. Neither difference was statistically significant [7].

Each group had ten people, and the study lasted six weeks. They measured only one marker in white blood cells, not muscle as Saladino’s theory suggests. With those limits, the study found no evidence that extra linoleic acid increased oxidative DNA damage.

The population data point the same way. Among 85,425 UK Biobank adults followed for almost 13 years, the top fifth for plasma omega-6 as a share of total fatty acids had 23% lower all-cause mortality than the bottom fifth [8].

That study also challenged an argument I believed for a year. The group with the highest ratio had 26% higher mortality. Both omega-6 and omega-3 were linked to lower mortality, but the link was stronger for omega-3 [8]. The authors thought the ratio result was probably due to omega-3.

Randomized trials don’t show much. In 19 studies with 6,461 adults followed for one to eight years, increasing omega-6 made little or no difference to deaths or heart problems overall. It did lower total cholesterol and might have reduced heart attacks, but the evidence for that is weak [9].

My own ratio was 3.6, which experts say is good. But that number didn’t tell me if I was getting enough of either fatty acid. I realized I might have been taking the wrong part of my fish oil for ten years.

The two trials that should trouble me

Two randomized trials are central to the main arguments against seed oils. Anyone who thinks this debate is settled should take a close look at them.

The Minnesota Coronary Experiment randomized 9,423 people across six mental hospitals and a nursing home between 1968 and 1973. The intervention replaced saturated fat with corn oil. Cholesterol fell 13.8% among participants measured again after a year or more, with no mortality benefit [10]. People kept leaving the institutions, ending their follow-up. The diet also pushed linoleic acid to 13.2% of calories, well above typical US intake of 5.5% to 6% [5].

The Sydney Diet Heart Study is the harder one. It randomized 458 men, 221 to safflower oil and safflower margarine and 237 to continue their usual diet. 86% had had a heart attack, on average about 11 weeks earlier. More of the intervention group died: 17.6% against 11.8%, a hazard ratio of 1.62, with a confidence interval from 1.00 to 2.64 [11].

I wish I could say the margarine was the reason. Margarine back then contained trans fats, but the exact makeup of this one wasn’t measured. However, the study’s authors considered this and ruled it out: the intervention also removed the usual margarines and shortenings, which were the main sources of trans fats at the time. So, trans fat intake probably went down, not up, and they thought it was unlikely to explain the results [11].

The study had clear limits: it involved men who had recently had heart problems, linoleic acid made up about 15% of their energy, there were several dietary changes, and the original protocol couldn’t be recovered. It was just one trial, in men who were already sick, at much higher intakes than usual. Still, it matters.

Why the evidence disagrees

My training taught me to look at each study and think about what kinds of errors it might have.

Plasma fatty acids depend on diet and metabolism. The UK Biobank authors adjusted for many known differences between participants. They still could not rule out factors they had missed or measured poorly, and they sampled blood once, at the start [8].

Randomization addresses confounding. Cochrane rated most of the clinical-outcome evidence low or very low certainty because of bias and imprecision [9].

Looking at all the studies together, I see two main gaps. The UK Biobank can’t prove cause and effect, and the trials only give rough estimates for real-world outcomes. No one has run a large, long-term trial at typical modern intake levels yet.

What the ears were for

No one planned to talk that night. My roommate brought up weight cutting, and soon everyone joined in, sharing stories about injuries, long hours inside, and the smell that never leaves a gym bag. We said things to each other we’d never say to a coach.

Someone joked that our parents should be prosecuted for signing us up. We all laughed, and while we half-meant it, none of us would have quit.

That’s what the ears meant. When you saw another guy across the room, you knew he’d gone through the same things you had, and you didn’t have to say a word.

I stopped wrestling in my mid-twenties, after my shoulder gave out for the last time. There was no final match or big decision, just a scan and a surgeon giving me practical advice. The training hall kept going every night without me. No one was unkind. What I wasn’t prepared for was how something that had shaped my whole life could just end, with everyone else carrying on while I stood outside.

Then there was nothing.

Nutrition groups offer the same sense of belonging, but without the physical cost. A jar on the counter shows everyone which side you’re on, and no one needs to check your ears.

That’s why the debate never ends. Each position gives you a group identity along with a health rule, and it’s harder to let go of the identity than the rule. I’ve been through this five times myself.

I went through all five phases on my own. Standing at the kitchen counter before anyone else was awake, blending butter into my coffee, I felt like I was part of something.

What I keep in the kitchen

At a work dinner a few weeks ago, a man sitting two seats away put down his fork and turned to me. “Andre, what do you think this was cooked in? Should I worry if it’s seed oils?” He wanted to know if his dinner was safe, and he was asking the doctor at the table.

The practical answer is simpler than the debate makes it seem. In the largest relevant study I found, 221,054 American health professionals were followed for up to 33 years. Replacing 10 grams of butter a day with plant oil was linked to a 17% lower risk of death [12]. This was an observational study, and the swap was modeled, not actually done.

Two of my own phases don’t look so good. Coconut oil raises LDL cholesterol by about 10 mg/dL compared to other vegetable oils, and none of the studies measured heart attacks or deaths [13]. Turning butter into ghee removes water and milk solids, so gram for gram, ghee has more saturated fat. As a percentage of total fat, butter and ghee are only a few points apart [14]. I swapped one for a more concentrated version and thought I was making a smart choice.

Olive oil, which I use now, compares well to butter. In a study of 92,383 people, it didn’t show a significant advantage over other vegetable oils [15].

What I told him

No, don’t worry about it, and eat your dinner.

The longer answer is that the bottle is just a distraction, and the scientific explanation is what convinces you. I went through five versions of this over 15 years, and each one was biochemically accurate. This is the Activate part of the Upward ARC, which is about what you put into your body. It’s also where marketing is strongest and the incentives are hardest to spot.

In one study, twenty people in a metabolic ward ate 508 more calories a day on an ultra-processed diet than on an unprocessed one, gaining about a kilogram in two weeks [16]. The trial didn’t test seed oil or figure out which differences in the diets caused the result. It was the overall eating pattern that changed how much people ate.

So, to answer his specific question: at the amounts people usually eat, there’s no human evidence that seed oils are especially harmful. Replacing butter and other saturated fats with plant oils lowers cholesterol, and studies link that swap to living longer. Whether purposely adding more omega-6 changes lifespan is still an open question.

Try this today

Each phase I went through added another rule. This list is about letting go of some of them.

Don’t treat the ratio as a final answer. In the UK Biobank data, both omega-6 and omega-3 were linked to lower mortality, and the authors believed the ratio was mostly influenced by omega-3. If you don’t eat oily fish often, start there before getting another test.

Stop overthinking and just keep two bottles: extra virgin olive oil for everyday cooking and finishing, and refined canola or high-oleic oil for frying and roasting. The difference between these sensible choices is so small that worrying about it costs you more than picking the wrong one.

Use frying oil only once, throw it out after cooking, and keep the pan below the oil’s smoke point. I do this as a kitchen habit, not because of any proven health outcome.

Ask what would make someone change their mind. For me, it would be a well-designed, independently funded trial at the amounts people actually eat. If I ever call a food poison and can’t answer that question, just stop reading.

Maybe I was just lucky

Throughout all five phases, my blood tests stayed normal. Maybe the type of fat mattered less than I believed. Maybe I was just lucky. I still keep butter in the fridge and use it in normal amounts.

Five times, an expert with a clear explanation convinced me before I checked the evidence myself, and five times I changed my mind later. I don’t regret making those changes.

I still miss that hallway and my wrestling tribe.

Stay healthy.

Andre

PS: I’ve told you my five eras. What was yours? The one you’d rather not admit to. Reply and tell me; I read every message and never share them. And if you know someone with strong opinions about oil who has never read a study on it, send this along. That’s how this newsletter grows, and the only way I want it to.

PPS: If someone forwarded this to you, you can get Under Load, my Sunday edition, here:

https://www.andreheeg.com

.

References

[1] Titans’ Robert Saleh sparks nutritional value debate with seed oil ban for players, team-provided meals. (2026, May). Fox News. https://www.foxnews.com/sports/titans-robert-saleh-sparks-nutritional-value-debate-seed-oil-ban-players-team-provided-meals

[2] Saladino, P. (2025, November 10). Don’t read this if you love your bacon. paulsaladinomd.com. https://www.paulsaladinomd.com/psmd-newsletters/dont-read-this-if-you-love-your-bacon

[3] Guyenet, S. J., & Carlson, S. E. (2015). Increase in adipose tissue linoleic acid of US adults in the last half century. Advances in Nutrition, 6(6), 660-664. https://doi.org/10.3945/an.115.009944

[4] de Kok, T. M., ten Vaarwerk, F., Zwingman, I., van Maanen, J. M., & Kleinjans, J. C. (1994). Peroxidation of linoleic, arachidonic and oleic acid in relation to the induction of oxidative DNA damage and cytogenetic effects. Carcinogenesis, 15(7), 1399-1404. https://doi.org/10.1093/carcin/15.7.1399

[5] Momin, S. R., Senn, M. K., Manichaikul, A., Tintle, N. L., Herrington, D. M., Rich, S. S., Kabagambe, E. K., & Wood, A. C. (2023). Dietary sources of linoleic acid (LA) differ by race/ethnicity in adults participating in NHANES between 2017-2018. Nutrients, 15(12), 2779. https://doi.org/10.3390/nu15122779

[6] Saladino, P. (2024, July 28). Seed oils & processed foods: How they’re harming you. paulsaladinomd.com. https://www.paulsaladinomd.com/psmd-newsletters/seed-oils-processed-foods-how-theyre-harming-you

[7] de Kok, T. M. C. M., Zwingman, I., Moonen, E. J., Schilderman, P. A. E. L., Rhijnsburger, E., Haenen, G. R. M. M., & Kleinjans, J. C. S. (2003). Analysis of oxidative DNA damage after human dietary supplementation with linoleic acid. Food and Chemical Toxicology, 41(3), 351-358. https://doi.org/10.1016/S0278-6915(02)00237-5

[8] Zhang, Y., Sun, Y., Yu, Q., Song, S., Brenna, J. T., Shen, Y., & Ye, K. (2024). Higher ratio of plasma omega-6/omega-3 fatty acids is associated with greater risk of all-cause, cancer, and cardiovascular mortality: A population-based cohort study in UK Biobank. eLife, 12, RP90132. https://doi.org/10.7554/eLife.90132

[9] Hooper, L., Al-Khudairy, L., Abdelhamid, A. S., Rees, K., Brainard, J. S., Brown, T. J., Ajabnoor, S. M., O’Brien, A. T., Winstanley, L. E., Donaldson, D. H., Song, F., & Deane, K. H. O. (2018). Omega-6 fats for the primary and secondary prevention of cardiovascular disease. Cochrane Database of Systematic Reviews, 2018(11), CD011094. https://doi.org/10.1002/14651858.CD011094.pub4

[10] Ramsden, C. E., Zamora, D., Majchrzak-Hong, S., Faurot, K. R., Broste, S. K., Frantz, R. P., Davis, J. M., Ringel, A., Suchindran, C. M., & Hibbeln, J. R. (2016). Re-evaluation of the traditional diet-heart hypothesis: Analysis of recovered data from Minnesota Coronary Experiment (1968-73). BMJ, 353, i1246. https://doi.org/10.1136/bmj.i1246

[11] Ramsden, C. E., Zamora, D., Leelarthaepin, B., Majchrzak-Hong, S. F., Faurot, K. R., Suchindran, C. M., Ringel, A., Davis, J. M., & Hibbeln, J. R. (2013). Use of dietary linoleic acid for secondary prevention of coronary heart disease and death: Evaluation of recovered data from the Sydney Diet Heart Study and updated meta-analysis. BMJ, 346, e8707. https://doi.org/10.1136/bmj.e8707

[12] Zhang, Y., Chadaideh, K. S., Li, Y., Li, Y., Gu, X., Liu, Y., Guasch-Ferré, M., Rimm, E. B., Hu, F. B., Willett, W. C., Stampfer, M. J., & Wang, D. D. (2025). Butter and plant-based oils intake and mortality. JAMA Internal Medicine, 185(5), 549-560. https://doi.org/10.1001/jamainternmed.2025.0205

[13] Neelakantan, N., Seah, J. Y. H., & van Dam, R. M. (2020). The effect of coconut oil consumption on cardiovascular risk factors: A systematic review and meta-analysis of clinical trials. Circulation, 141(10), 803-814. https://doi.org/10.1161/CIRCULATIONAHA.119.043052

[14] U.S. Department of Agriculture, Agricultural Research Service. (2019). FoodData Central: Butter, salted (FDC 173410); Butter, clarified (ghee) (FDC 171314).

https://fdc.nal.usda.gov

[15] Guasch-Ferré, M., Li, Y., Willett, W. C., Sun, Q., Sampson, L., Salas-Salvadó, J., Martínez-González, M. A., Stampfer, M. J., & Hu, F. B. (2022). Consumption of olive oil and risk of total and cause-specific mortality among U.S. adults. Journal of the American College of Cardiology, 79(2), 101-112. https://doi.org/10.1016/j.jacc.2021.10.041

[16] Hall, K. D., Ayuketah, A., Brychta, R., Cai, H., Cassimatis, T., Chen, K. Y., Chung, S. T., Costa, E., Courville, A., Darcey, V., Fletcher, L. A., Forde, C. G., Gharib, A. M., Guo, J., Howard, R., Joseph, P. V., McGehee, S., Ouwerkerk, R., Raisinger, K., … Zhou, M. (2019). Ultra-processed diets cause excess calorie intake and weight gain: An inpatient randomized controlled trial of ad libitum food intake. Cell Metabolism, 30(1), 67-77.e3. https://doi.org/10.1016/j.cmet.2019.05.008

What?

Researchers led by Parco Siu in Hong Kong assigned 315 inactive adults with central obesity to 3 groups: one group performed one workout a week, another performed 3, and the third attended health education classes. After 16 weeks, the once-a-week group lost 0.8 kg of fat compared to the control, while the 3-times-a-week group lost 1.0 kg. The difference between the 2 exercise groups was too small to be significant. Both groups reduced their waist size by about 2 cm. The study was published in Nature Communications.

There are two important details that most reports missed. The exercise involved supervised treadmill sessions: 4 intervals of 4 minutes each at 85-95% of peak heart rate, with 3 minutes of easy walking between intervals. For the once-a-week group, the session meant doing 3 of these blocks in a row with rest breaks, making it almost 2 hours at the gym, not just a long walk.

So what?

The main difference between the groups was in fitness. The once-a-week group improved their VO2 peak by 1.5 ml/kg/min, while the 3-times-a-week group improved by 2.6. 16 weeks after the training ended, only the 3-times-a-week group still had better fitness than the control group. By then, the fat loss was gone, but both groups kept their smaller waists.

I’ve said before that VO2 max is the best measure of how long you’ll live and how well you’ll function. From that perspective, the headline is only partly true. The once-a-week plan matched the others for fat loss, but it didn’t keep up in fitness; fitness was the lasting benefit at week 32.

The other side is important too. For living longer, how you spread out your workouts might not matter much. A 2025 review of 21 studies found that people who exercise only on weekends and those who exercise more regularly both experienced similar reductions in death rates. If you can only fit in one session a week, it’s still worth doing.

The real difference came from working at 85-95% of your peak heart rate.

Now what?

• Try the workout as it was tested: start with 5 minutes of easy effort, then do 4 rounds of 4 minutes hard and 3 minutes easy, and finish with another 5 minutes of easy effort. The whole session takes about 35 minutes.

• ‘Hard’ means you shouldn’t be able to finish a sentence. If you can talk easily during the 4-minute intervals, you’re not pushing hard enough. You don’t need a heart rate monitor for this.

• Aim for 3 sessions a week if you can, since that group kept their fitness gains. The study didn’t test 2 sessions a week, so I can’t speak to that.

• If your week gets busy, still try to fit in at least one session. Even one workout was better than just attending the education class.

• Don’t let the scale be your only measure. Choose a set route or stairwell, time yourself today, and check your progress again in 8 weeks.

8 weeks from today is October 7. Mark your calendar for your retest.

Stay healthy.

Andre

The shop sold vials. The shipping terms said the contents were for lab research only and not for people. Sites include that so whatever happens next is your responsibility.

I have both a medical and dental degree, but I was still about to send money to strangers for something I planned to inject into myself.

By August 2024, my wife was putting my socks on for me. Underwear was even harder because you have to balance on one leg. I washed my face in stages. After 18 months of this, things only got worse. On work mornings with travel, I took the strongest painkiller I had.

I wore headphones most of the day. That August, while half-listening to a podcast, I heard Andrew Huberman tell Joe Rogan something about a compound called BPC-157:

“while only animal data, it’s very clear, you know, it has the propensity to encourage fibroblasts, which is cells that, you know, make up things like, you know, tendon and cartilage, et cetera, and can really repair tissues… I certainly have experienced it can help repair things.” [1]

I missed the warning. The words that stayed with me were tendon and cartilage.

I had heard about it before and ignored it. That afternoon, I ended up on a vendor’s website.

The vote that changed nothing

I first heard about BPC-157 in July 2021 from the same two men on the same show [2]. Three years later, I was at my lowest point when it came up again. Two years after that, on July 23, an FDA advisory panel voted 8 to 6 to recommend letting pharmacies compound it, even though the agency’s own reviewers disagreed. Eight panelists were recent appointees, and six of them ran clinics that sell peptides. One person voted yes but admitted the data was disappointingly incomplete [3].

But nothing changed after that. A panel can only recommend. The list of what pharmacies can legally make hasn’t changed since February 2019 [4], so no pharmacy in America can legally make BPC-157 today. The vote only changed what people expect might happen.

There was a vote, but still not a single randomized trial in humans. That’s why people keep asking me the same question: Are peptides safe?

No one can answer that, because the word itself doesn’t refer to a single thing.

The word is a size

Insulin is a peptide. It has 51 amino acids and is the reason a 14-year-old in Toronto, who weighed just 65 pounds when admitted, lived another 13 years [5]. Semaglutide (Ozempic/Wegovy) is also a peptide, and someone on your leadership team is probably using it quietly.

A peptide is simply a short chain of amino acids. That’s the definition. In the U.S., regulators set the cutoff at 40. Anything above that is considered a biologic, which is protected from copies for 12 years and can’t be made by compounding pharmacies. Regular drugs get 5 years [6][7]. Tirzepatide (Mounjaro/Zepbound) is just under the limit, at 39 [8].

That number only affects the paperwork and nothing else.

Abud Bakri is an internist who has used these compounds himself and says so, sits on the medical commission of Enhanced, which sells peptides, and has consulted for a group planning a BPC-157 trial. On Huberman’s show in June:

“everyone online talks about peptides are good or peptides are bad. There’s no actual scientific category of peptides that gives you a functional definition that’s discussable between two people. Because what do you mean by peptide? Do you mean carnosine or do you mean [retatrutide]?” [9]

What I ask myself before taking anything

Three questions, in order.

Has this ever been given to humans in a study I can read? Who funded that study, and do they also sell the compound? And does the result actually matter in real life, or is it just a number in my blood that’s never been shown to make a difference?

Most so-called longevity peptides don’t even pass the first question.

One lab in Zagreb

In the early 1980s, a group in Croatia went looking for whatever keeps the stomach from digesting itself. By 1989 they said they had it: a fragment of a larger protein, 15 amino acids long [10][11].

The full sequence of that larger protein has never been published. When a reporter asked why, Predrag Sikirić said that if you have your own child, you want it to be yours forever. Anna Mapp, a chemist at Michigan and president of the American Peptide Society, told the same reporter that without the full sequence, it’s impossible to reproduce the original work [11].

Then came the animal studies: rats with severed tendons, cut ligaments, burns, and crushed muscles healed faster, again and again, mostly in studies by the same group. About four out of five BPC-157 papers on PubMed list Sikirić or his Zagreb colleague as an author, a number his critics published last year, and he disputed in the same journal [12].

There are no randomized controlled trials in humans. A systematic review last year looked at 544 papers and included 36; 35 were animal studies [13]. The only human study was a survey: 12 patients who had already received knee injections were asked how they felt afterward; 7 said they felt better, but there was no placebo and no blinding [14]. The rest are a small intravenous pilot in two people [15] and a couple of Croatian trials from the early 2000s where the compound was given as an enema and never fully published.

Bakri says that when researchers checked those patients’ blood afterward, they couldn’t find the compound [9]. Maybe it stayed local, broke down too quickly to measure, or was never absorbed. No one outside that group can verify it.

And almost no one takes it the way those trials did.

What I won’t write down

I should be clear that I’m not a purist. I’m curious and have tried plenty of things on myself that aren’t standard medicine. I’ve written before about experimenting with psychedelics. I know my own body, and I understand physiology and pharmacology well enough to take a calculated risk. I’m comfortable being the one who finds out.

What I get from that is a study with one participant, me, unblinded, and run by someone who wanted it to work. That’s a long way from real advice. I wouldn’t give it to my own family.

People still ask me for prescriptions. Metformin, because they read about its link to longevity. Stimulants. Testosterone. And lately, peptides.

Some of these would be easy to prescribe, and the risk would be small. I could write the prescription in 20 seconds and say what everyone says: this is off-label, I’ve explained it to you, you’re doing it at your own risk, I take no responsibility. All of that is true, but it still makes me the one who signed.

Most of my surgical years went on cancers of the mouth: the lip, the tongue, the floor of the mouth, the lining of the cheek. Surgery is the backbone; radiation comes after it, sometimes with chemotherapy alongside. Surgery means cutting in three dimensions with a margin of a centimeter around the tumor. Take something the size of a walnut out of the tongue, and you have changed how that person speaks for the rest of their life, how they move food around their mouth, whether they can swallow at all.

Most were men in their sixties, smokers, with a lesion on the side of the tongue they’d called a mouth ulcer for months. I would sit down and explain the situation. The consequences would be permanent, and they’d be reminded every time they spoke. It was their best chance, but no one could promise it wouldn’t return.

They said yes, almost all of them.

I would see them months later, eating, talking, holding a cup of coffee.

I’ve already been the person who said yes and then watched someone go home and live with the outcome. That’s why I won’t do it casually for something untested, just because someone wants it.

The argument back is always the same. If you don’t, someone else will.

Fine. Then someone else can take responsibility for that.

The correction that didn’t travel

In July 2021, Huberman told Rogan that things like it “definitely do accelerate the healing of an injury and there’s no question about that.” Rogan, same conversation: “I’ve used it myself, and I had a tendonitis in my elbow that I just could not fix. I started using [BPC-157]. It was gone in two weeks” [2].

By August 2024, Huberman had moved. The sentence now started with “while only animal data” [1]. And 5 months before that, on his own show, he had gone further still: BPC-157 may raise tumor growth risk through the same blood-vessel mechanism that makes it interesting, and he does not suggest anyone buy black-market peptides [16]. He has since said he took it himself, on a prescription, and no longer does [9].

He was more cautious than people think, and he became even more careful as time went on.

Still, I found myself on a vendor’s website.

The warning and the claim both leave the podcast studio, but only the claim spreads.

The evidence trail is contaminated too

Say you do the responsible thing and check. The American trials registry is where a careful person looks, and as of August 4 it returns Phase 2 studies for BPC-157 and TB-500, marked recruiting.

Three of the records in that cluster say inside their own text that they are fictional or mock entries [17].

They seem like practice submissions that accidentally got out of a test system. I have no proof anyone meant to mislead. But the effect is the same. You search for evidence and find something that looks real, from a sponsor with a real name, marked as enrolling patients. The BPC-157 record doesn’t have any disclaimer.

The Wolverine stack

Few people take BPC-157 alone, and the bundles have names.

BPC-157 with TB-500 is sold as the Wolverine stack. Add copper peptide, and it becomes the glow stack. Someone picked those names. An adult decided that a man injecting two untested compounds into his shoulder should picture himself as a comic book hero with claws. It works, because people buy it. I used the male pronouns on purpose.

Bakri described what he calls the Trinity stack: a GLP-1, a growth hormone drug, a hormone layer on top. “A lot of these transformations you see in CEOs and celebrities and stuff is using a combination of those three things,” he said. On whether it’s healthy: “We’ll find out” [9].

We’ll find out. By watching what happens to people like you.

He also explained how people get there: buy one, see a result, add three more, and “the average sale value goes up from these research sites” [9]. I couldn’t find any study on what these combinations do together.

The GLP-1s are the exception, and the reason everyone else is comfortable holding a syringe. Semaglutide and tirzepatide went through the full process, and they are the best evidence in this field.

I couldn’t find any published analysis of what’s actually in gray-market BPC-157. Researchers bought semaglutide from online sellers. The vials were overfilled with material that was only 7.7% to 14.4% semaglutide, against a label claiming 99%, which still left the dose 28% to 39% above what the label promised. Every sample carried bacterial endotoxin. Mostly unknown material, and more drug than you think [18].

Bakri told a story about a man who ordered a weight loss compound and saw his skin darken, only to realize he was injecting a tanning peptide [9]. That’s the kind of mistake you can see in the mirror. The others, you can’t.

Insulin and the GLP-1s are medicine, with the trials to prove it. BPC-157 is unfinished. TB-500 is a 7-amino-acid piece of a bigger molecule whose own trial record is mixed, and the fragment inherits none of it [19]. Melanotan II, the tanning one, has published case reports of muscle breakdown, kidney infarction, priapism, and new atypical moles [20][21][22][23]. KPV, dihexa, PEG-MGF, and epitalon have no registered Western human trial, which didn’t stop the July panel recommending KPV alongside BPC-157 [3].

Where I’m on thin ice

I can’t say BPC-157 doesn’t work. The animal data is better than I expected after a week of research, and there’s no published series of humans harmed by it either because no one has done the study that would answer that question.

And by my own three questions, my own back wouldn’t count as evidence. One participant, no blinding, no comparison group, and a condition that sometimes gets better on its own. I know that. I’d still begin with what I did before. If physiotherapy fails, you’ve lost 12 weeks. If a vial fails, you can’t take back whatever it already did.

This is the Activate pillar of the Upward ARC, the part about what you put into your body, and it’s where that risk hits hardest.

Try this today

Some of you are already taking something. Some of you are just thinking about it. This is for both groups.

If you have any history of cancer, or anything undiagnosed, this is where I stop being neutral. BPC-157 appears to work partly by growing blood vessels. Tumors need blood vessels. Nobody has run the study that would tell us whether that matters in a person, and I wouldn’t volunteer to find out. Huberman said the same on his own show, and almost nobody quotes that one [16]. If you compete under anti-doping rules, all three of these are prohibited at all times on the WADA list: BPC-157 as a non-approved substance, TB-500 as a thymosin derivative, MOTS-c as a metabolic modulator. A prescription is no defense [24].

Ask yourself those three questions before trying any compound. Most options will drop off the list.

Find out what’s actually in the vial, and ask about the markup. Who made it, which lab tested it, and is that lab independent from the seller? Then ask your clinician what the pharmacy charges them and what they charge you. That price gap is legal in many places and goes into someone’s pocket. Treat the seller’s certificate as marketing: in one analysis, two custom-made peptides were found to be 20% and 43% undeclared mannitol by weight, which standard purity tests wouldn’t catch [25].

Decide what failure looks like before you start. What will you measure, by when, and what result will make you stop? Write it down. Without this, every intervention seems to work forever.

Two years of boring

Looking at that transfer form, I realized what I had become: a man in an alley, buying something from a stranger and just hoping.

I had become someone willing to put an unknown substance into my body just because I couldn’t put on a sock. No vial could fix what that said about me.

So I chose the other path. I sought guidance from physiotherapists, back pain specialists, nutritionists, and others. I rebuilt my training routine twice, changed my diet, lost weight, and kept habits I still follow, like a walk before my first call and a proper shutdown routine after 10pm. It took months, but it worked. I haven’t needed a painkiller in almost two years.

At some point, my wife stopped needing to help me with my socks. I can’t say which morning it was, and that’s how I know it was the slow, steady approach that worked.

I’d listened to every podcast. The only thing I never did was take action on a random Tuesday, in a life that doesn’t stop for experiments.

I was lucky because of where I lived. The compound was hard to get in Germany, and that delay gave the rational part of me time to catch up with the desperate part. If I’d been somewhere with next-day delivery that August, things might have turned out differently.

Stay healthy.

Andre

PS: I’m not judging anyone, because I was one click away from doing the same thing. Have you ever come close? It doesn’t have to be peptides, just anything you considered when pain or exhaustion dragged on too long. Reply and tell me about it. I read every message, and I never share them. If you know someone who needs this, forward this edition to them. This is how this newsletter grows, and it’s the only way I want it to.

PPS: If a friend forwarded this to you, you can get Under Load, my Sunday edition, here:

https://www.andreheeg.com

.

References

[1] Rogan, J. (Host). (2024, August 27). #2195 – Andrew Huberman [Audio podcast episode]. In The Joe Rogan Experience. Speaker-labeled transcript, approximately 3:02:52.

[2] Rogan, J. (Host). (2021, July 14). #1683 – Andrew Huberman [Audio podcast episode]. In The Joe Rogan Experience. Approximately 2:39:14-2:40:37. Automated transcript; both speakers render the compound inconsistently, and bracketed corrections are marked.

[3] Lovelace, B., Jr., & Miller, S. G. (2026, July 23). FDA panel recommends easing some peptide restrictions despite disapproval from scientists. NBC News. https://www.nbcnews.com/health/health-news/peptides-restrictions-ease-fda-panel-recommend-bpc-157-scientists-rcna588879

[4] List of bulk drug substances that can be used to compound drug products in accordance with section 503A of the Federal Food, Drug, and Cosmetic Act, 84 Fed. Reg. 4696 (February 19, 2019), codified at 21 C.F.R. § 216.23. No subsequent amendment as of August 2026.

[5] Rogol, A. D., Laffel, L. M., Bode, B., & Sperling, M. A. (2023). Celebration of a century of insulin therapy in children with type 1 diabetes. Archives of Disease in Childhood, 108(1), 3-10. https://doi.org/10.1136/archdischild-2022-323975

[6] Definitions, 21 C.F.R. § 600.3(h)(6).

[7] Biologics Price Competition and Innovation Act of 2009, 42 U.S.C. § 262(k)(7); Drug Price Competition and Patent Term Restoration Act of 1984, 21 U.S.C. § 355(j)(5)(F)(ii); Federal Food, Drug, and Cosmetic Act § 503A, 21 U.S.C. § 353a.

[8] Coskun, T., Sloop, K. W., Loghin, C., Alsina-Fernandez, J., Urva, S., Bokvist, K. B., Cui, X., Briere, D. A., Cabrera, O., Roell, W. C., Kuchibhotla, U., Moyers, J. S., Benson, C. T., Gimeno, R. E., D’Alessio, D. A., & Haupt, A. (2018). LY3298176, a novel dual GIP and GLP-1 receptor agonist for the treatment of type 2 diabetes mellitus: From discovery to clinical proof of concept. Molecular Metabolism, 18, 3-14. https://doi.org/10.1016/j.molmet.2018.09.009

[9] Huberman, A. D. (Host). (2026, June 1). Peptides: The science, uses & safety | Dr. Abud Bakri [Audio podcast episode]. In Huberman Lab. Quotations at approximately 0:00:29, 0:21:12, 0:34:15, 2:30:20 and 2:37:50.

[10] Józwiak, M., Bauer, M., Kamysz, W., & Kleczkowska, P. (2025). Multifunctionality and possible medical application of the BPC 157 peptide: Literature and patent review. Pharmaceuticals, 18(2), 185. https://doi.org/10.3390/ph18020185

[11] Talpos, S. (2026, May 29). A peptide, a secretive scientist, and a debate over evidence. Undark Magazine. https://undark.org/2026/05/29/stress-test-bpc-157-history/ (Co-published by STAT News, June 1, 2026.)

[12] Józwiak, M., Bauer, M., Kamysz, W., & Kleczkowska, P. (2025). Reply to Sikiric et al. Comment on “Józwiak et al. Multifunctionality and possible medical application of the BPC 157 peptide: Literature and patent review.” Pharmaceuticals, 18(10), 1451. https://doi.org/10.3390/ph18101451

[13] Vasireddi, N., Hahamyan, H., Salata, M. J., Karns, M., Calcei, J. G., Voos, J. E., & Apostolakos, J. M. (2025). Emerging use of BPC-157 in orthopaedic sports medicine: A systematic review. HSS Journal, 21(4), 485-495. https://doi.org/10.1177/15563316251355551

[14] Lee, E., & Padgett, B. (2021). Intra-articular injection of BPC 157 for multiple types of knee pain. Alternative Therapies in Health and Medicine, 27(4), 8-13.

[15] Lee, E., & Burgess, K. (2025). Safety of intravenous infusion of BPC157 in humans: A pilot study. Alternative Therapies in Health and Medicine, 31(5), 20-24.

[16] Huberman, A. D. (Host). (2024, April 1). Benefits & risks of peptide therapeutics for physical & mental health [Audio podcast episode]. In Huberman Lab. https://www.hubermanlab.com/episode/benefits-risks-of-peptide-therapeutics-for-physical-mental-health

[17] U.S. National Library of Medicine. (2026). ClinicalTrials.gov records NCT07437547, NCT07487363, NCT07481734 and NCT07437560, first posted February-March 2026. Retrieved August 4, 2026.

[18] Ashraf, A. R., Mackey, T. K., Vida, R. G., Kulcsár, G., Schmidt, J., Balázs, O., Domián, B. M., Li, J., Csákó, I., & Fittler, A. (2024). Multifactor quality and safety analysis of semaglutide products sold by online sellers without a prescription: Market surveillance, content analysis, and product purchase evaluation study. Journal of Medical Internet Research, 26, e65440. https://doi.org/10.2196/65440

[19] Sosne, G., Kleinman, H. K., Springs, C., Gross, R. H., Sung, J., & Kang, S. (2023). 0.1% RGN-259 (thymosin β4) ophthalmic solution promotes healing and improves comfort in neurotrophic keratopathy patients in a randomized, placebo-controlled, double-masked Phase III clinical trial. International Journal of Molecular Sciences, 24(1), 554. https://doi.org/10.3390/ijms24010554 (Primary endpoint not met, p=0.0656; funded by ReGenTree, with authors employed by the sponsor or its parent.)

[20] Nelson, M. E., Bryant, S. M., & Aks, S. E. (2012). Melanotan II injection resulting in systemic toxicity and rhabdomyolysis. Clinical Toxicology, 50(10), 1169-1173. https://doi.org/10.3109/15563650.2012.740637

[21] Peters, B., Hadimeri, H., Wahlberg, R., & Afghahi, H. (2020). Melanotan II: A possible cause of renal infarction. CEN Case Reports, 9(2), 159-161. https://doi.org/10.1007/s13730-020-00446-0

[22] Dreyer, B. A., Amer, T., & Fraser, M. (2019). Melanotan-induced priapism: A hard-earned tan. BMJ Case Reports, 12(2), e227644. https://doi.org/10.1136/bcr-2018-227644

[23] Reid, C., Fitzgerald, T., Fabre, A., & Kirby, B. (2013). Atypical melanocytic naevi following melanotan injection. Irish Medical Journal, 106(5), 148-149.

[24] World Anti-Doping Agency. (2026). The 2026 prohibited list. BPC-157 under S0 (non-approved substances); thymosin beta-4 and its derivatives, including TB-500, under S2.3 (growth factors); MOTS-c under S4.4 (AMPK activators, metabolic modulators). All prohibited at all times.

[25] Choules, M. P., Bisson, J., Simmler, C., McAlpine, J. B., Giancaspro, G., Bzhelyansky, A., Niemitz, M., & Pauli, G. F. (2020). NMR reveals an undeclared constituent in custom synthetic peptides. Journal of Pharmaceutical and Biomedical Analysis, 178, 112915. https://doi.org/10.1016/j.jpba.2019.112915