I slid 20 kilograms onto each side of the bar and stepped under it.
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.