After a poor night of sleep, making it through a workout can feel more challenging. Is it better to push through, or take the day off?Organic Media/Getty Images
Thanks to the growth of wearable devices, we know more about our sleep than ever before. Our smartwatches or rings can tell us when we fell asleep, how long we stayed asleep and the duration of our deep sleep. They can then use that data to tell us whether working out that day is recommended. Some people use their sleep scores and app-generated exercise advice to determine how to modify a planned workout or whether they should skip a sweat session entirely.
But how much does sleep really affect our ability to exercise? Is it better to push through a workout after a poor night of sleep, or should we relax on the couch instead?
“If we wait for perfection every single day, we won’t move often,” says Jonathan Charest, an adjunct professor of psychology at Université Laval, who studies the impact of sleep on athletic performance. “Moving is key.”
Most adults need between seven and nine hours of sleep a night. After a loss of even one or two hours of sleep, your brain and body might feel sluggish, and you might experience greater irritability, cravings and headaches. That can make your usual workout feel more daunting and demanding, and the diminished cognitive function that comes along with it can slow reaction times and increase injury risk. But according to experts, getting in some kind of movement, even a modified session, is still a good idea.
How lack of sleep affects your ability to exercise
“When you wake up after a bad night, you don’t necessarily have the same cognitive function that you may after a good night’s sleep,” says David T. Martin, a cardiologist and cardiac electrophysiologist at Mass General Brigham.
That can affect certain kinds of exercise where there’s a low margin of error between safety and injury, and where co-ordination is crucial. In contact sports, for example, “a fraction of a second will make the difference between a concussion and avoiding a big hit,” says Charest.
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When it comes to strength training, studies show that a single night of sleep deprivation may not meaningfully affect your ability to perform a maximum effort lift, but since lack of sleep also increases our perceived effort and exertion, those movements might feel more challenging.
“We play tricks on ourselves,” says Charest. “You perceive pain a little bit more acutely, more painful than it really is. And fatigue is all of a sudden more bothersome.”
You might feel that during the latter half of a long run or climbing a hill in spin class, but there’s likely nothing actually keeping your muscles from continuing to work.
“If it’s a one-night thing, you can get over it very quickly and it shouldn’t impact your ability to exercise or to compete,” says Martin.
Although exercise may feel more challenging, there’s likely nothing actually keeping your muscles from working.Liudmila Chernetska/Getty Images
So should you hit the gym if you’ve had a poor night of sleep?
Instead of skipping the gym entirely, consider making some adjustments for safety, recovery and overall enjoyment.
Make time for a longer warmup and assess how your body is feeling once it’s in motion, says Charest. He also recommends having a Plan B workout that you can do in the same place to make it more likely you’ll still get some movement.
While most studies show that muscle strength does not meaningfully decrease after just a single night of poor sleep, you might want to skip a personal record attempt anyway, since your ability to react quickly to pain can be compromised.
That said, there are some workarounds. One meta-analysis from the Journal of Science and Medicine in Sport found that with external motivation, such as caffeine ingestion and working out in groups, individuals could perform compound movements such as squats and bench presses slightly better. Napping prior to training was found to help as well, as was exercising in the morning when motivation is likely to be higher.
What exercise regimen is best for sleep?
If you can modify your workout, consider shifting to lower weight and higher repetition volume.
If you’ve planned a cardiovascular workout, such as a run, consider a shorter distance since the increase in perceived exertion can make those later miles feel tougher. You can also try interval work on a track where you can call it quits easily if you feel discomfort.
All that said, there’s really no one-fits-all answer. “The line will move with each athlete,” says Charest. “It’s always very, very individualized.”
For wearable devotees, that also means considering what your body is telling you, rather than just following the advice of your device, which may not always be accurate.
Nudging yourself to exercise might also help improve your sleep the following night by enhancing mood, reducing stress and regulating body temperature. Even a brisk walk counts, according to a 2025 article in the journal Biological Timing and Sleep.
“You need to move,” says Charest. “If you find an excuse, just find a solution after that. And the solution is rarely the couch.”
Alyssa Ages is a journalist and the author of Secrets of Giants: A Journey to Uncover the True Meaning of Strength. She is also a strongman competitor and endurance athlete, as well as a former personal trainer and group fitness instructor.