One of the typical recommendations to combat insomnia is to do some physical exercise during the day. However, it is also known that if intense sport is practiced just before going to sleep, it can also alter our sleep. What is the perfect balance?
A new meta-analysis published in Sleep Medicine Reviews reviews data from 15 articles studying the effect of a single session of intense exercise before bed in healthy young and middle-aged adults.
And, although no two bodies are alike, the researchers found that the combination of factors would interact to enhance or modulate the effects of exercise on sleep. “When we reviewed the literature on this work, we found that there were a lot of mixed results,” says Melodee Mograss, a cognitive neuropsychologist and researcher at PERFORM Sleep Lab. ” Some depended on the timing of exercise, others on the fitness level of study participants. or even the kind of exercise . “
Timing is (almost) everything
The researchers combined data from the 15 studies and performed a statistical analysis that examined variables such as the timing of exercise (early evening or late at night) and the hours between cessation of exercise and bedtime (less than two hours, about two hours, and two to four hours).
Additional variables included participants’ fitness level (sedentary or physically active), intensity threshold, and exercise duration. They also looked at how certain types of exercise influenced sleep.
“Overall, our analysis showed that when exercise ended two hours before bedtime, there were benefits to sleep, including promoting sleep onset and longer sleep duration,” explains study lead author Emmanuel Frimpong. “ On the other hand, when the exercise ended less than two hours before bedtime, sleep was negatively affected. The participants took longer to fall asleep and the duration of sleep decreased . “
A more detailed analysis provided the following results:
- The high-intensity exercise performed in the middle of the afternoon promoted the onset of sleep and improved the duration of sleep, especially when performed by sedentary people.
- Cycling exercises were found to benefit participants the most in terms of initiation and deep sleep.
- However, high-intensity exercise, regardless of time, contributed to a slight decrease in rapid eye movement (REM) stage of sleep, the stage of sleep that is commonly associated with dream experiences. Studies suggest that decreased REM sleep can negatively affect cognitive tasks if the information is complex and emotionally stimulating, but not if the information is easy or neutral.
Different effects for early risers and night owls
” According to our review, for healthy, young and middle-aged adults with no history of sleep disorders, physical exercise should be done, if possible, in the mid-afternoon, ” concludes Frimpong.
“People should also maintain a consistent exercise schedule , as exercising at different times in the afternoon could cause sleep disturbances. People should also consider whether they are early risers or night owls. High intensity exercise done late at night can cause morning-type sleep disturbances in people. “
“And finally, you should also carry out sleep hygiene strategies, such as showering between the cessation of exercise and bedtime and avoiding heavy meals or drinking plenty of water before going to bed.”
