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How does physical exercise affect sleep?
Last reviewed: 02.07.2025
Many trainers and doctors recommend increasing daytime physical activity to improve the quality of nighttime sleep. In order to analyze the relationship between moderate-intensity training and nighttime rest, scientists from Concordia University studied data from previous scientific studies. As a result, it was found that physical exercise, which was carried out at least 2 hours before going to bed, had a positive effect on its quality. However, exercises carried out immediately before bedtime had a rather unfavorable effect: people were unable to fall asleep longer, and overall slept less.
During the testing, scientists analyzed 15 studies involving almost two hundred people. Some of the participants were not physically active, while others were in good physical shape and did not complain about the quality of their sleep. The average age of the participants was from 18 to 50 years.
Subjects were assessed using polysomnography, actigraphy, or subjective judgment of the impact of physical activity on sleep. What did the experts find out?
If the training was completed at least 2 hours before going to bed, then falling asleep was faster and the night's rest was long. This effect was especially noticeable in people who had not previously been very physically active. If the training was conducted less than two hours before going to bed, then the effect was the opposite: people could not fall asleep for a long time, and the night's rest was intermittent and short.
Scientists noted that the best sleep-impacting exercise was half an hour to an hour of moderate intensity. And cycling was recognized as the most effective and beneficial exercise.
High-intensity exercise, regardless of how often it was performed, had a negative effect on REM sleep, which is associated with dreaming. This suggests that high-intensity activity may have a negative effect on participants’ cognitive abilities later on. This may be because too much exercise increases arousal and body temperature, puts the body into a state of stress, and leads to sympathetic hyperactivity. As a result, the circadian rhythm may be inhibited, which leads to a slow release of melatonin, a hormone associated with sleepiness at night.
Representatives of the Academy of Nutrition and Dietetics note that high-intensity training will be most beneficial if it is carried out in the first half of the day. Only in this case can you expect a normal ratio of physical activity and quality sleep. However, it is necessary to take into account the individual characteristics of the body. You should listen to your body, feelings, to understand which regime is right for you and when it needs to be adjusted.
The results of the study were published on the pages of Science Direct