Does Working Out Before Bed Disrupt Your Sleep?

For some, doing a workout before sleep is the key ingredient for a good night's rest. But for others, not so much. How important is the timing of exercise, really? And is it bad to work out before bed?

There's no doubt that exercise, in general, is good for sleep. "Research shows that having a consistent exercise routine helps with various aspects of health, including helping you sleep better and more soundly", said Jason Machowsky, CSCS., exercise physiologist and board-certified sports dietitian.

In a 2017 review in Advances in Preventive Medicine, a large majority of studies analysed found that exercise improved sleep quality, as well as the amount of sleep participants were able to secure.

But what about the timing of your workout?

A 2021 systematic review and meta-analysis in Sleep Medicine Reviews analysed 15 studies on healthy young and middle-aged adults that looked at the impact of doing high-intensity exercise in the evening. The research concluded that evening exercise performed two to four hours prior to bedtime did not disrupt sleep compared with control groups (who did no exercise). In fact, those who worked out two hours before bed got to sleep faster and slept for longer, and workouts of 30 to 60 minutes were found to be the best for sleep.

Evening exercise may facilitate sleep by heating up the body and decreasing stress and anxiety, said the authors. When your body cools down, it triggers sleepiness—something referred to as the "warm-bath effect", which has been found to improve sleep, research has shown. (Your body will naturally cool down before bed, but a warm bath—or exercise—can kick off that process.)

What you probably shouldn't do is end a workout and immediately hop into bed. A systematic review of 23 studies found that certain parameters of sleep quality were improved with evening exercise, as long as the workout ended at least an hour before bed. Less than that may not allow your cardiovascular system to recover fully before bed, meaning you'll slip between the sheets with a higher heart rate and a nervous system that's all riled up, impeding sleep.

Despite the research, a workout before bed might not be right for you. That's because whether or not exercise at night disrupts your ability to sleep is individual, explained Shelby Harris, PsyD, clinical psychologist and author of "The Women's Guide to Overcoming Insomnia". For some people, vigorous exercise within a few hours before bed makes it tougher to fall asleep, she said, adding that "while this isn't true for everyone, it can be an issue for many people".

What's important is knowing how your body reacts to exercise, and letting that (along with your preferences and life demands) inform the best time to schedule it for you. You may also find that certain types of exercise affect your sleep more than others. It's a good idea to be mindful about the type of movement you choose for a pre-bed sweat session.

Certain athletes might be able to do a HIIT workout, have a quick bedtime snack and then snooze without worry. Meanwhile, others may go for a run and then lay awake feeling too stimulated to sleep. It's all about your individual response.

"If you notice you do a really hard HIIT workout before bed and can't sleep, you're probably one of those people who should not do intense exercise late at night", Machowsky said.

If you're struggling with your sleep, adjust the timing of exercise or the type you're doing. A 2019 review of 14 studies found that moderate exercise was better for improving sleep quality compared with more vigorous bouts. Walking—even modestly increasing step count—promoted better sleep.

(Related: What Is Power Walking—and Do You Need to Add It to Your Weekly Workouts?)

If you are doing high-intensity exercise, research in Sleep Medicine Reviews suggests scheduling the workout to end at least an hour before bed so that it doesn't disrupt your sleep or interrupt the practice of healthy pre-bed routines like shutting off screens.

What does this mean for you? While research is generally positive when it comes to the impact exercise has on sleep quality, it can't predict how you'll react. Harris recommended experimenting to find your optimal workout time. If you're looking to your workout to help unwind, Harris said that many people like slow-flow and restorative yoga or stretching at night to encourage quality sleep.

Also important: exercise, in general, can negatively impact sleep for people who are experiencing overtraining syndrome, Machowsky said. "One hallmark symptom [of overtraining syndrome] is poor, restless sleep because the body doesn't have the energy it needs to repair itself", he explained.

In that case, the problem isn't about what time of day you're working out. Overtraining isn't caused by one tough workout followed by inadequate fuelling, but by the body not being given consistent and ample time to continuously recover with quality nutrition and other tools.

Overtraining isn't the result of doing one especially difficult workout or occasionally skipping a meal. Instead, overtraining is when you consistently neglect to give your body the time it requires to recover between workouts. It also describes repeatedly skipping or not eating adequately nutritious meals.

Words by Jessica Migala