The common recommendation to avoid physical activity in the four hours prior to bed due to its potentially negative effects on sleep might actually be false, at least according to a new review of the scientific literature on the topic.
Having looked at 23 studies which have met the inclusion criteria, the authors of the new paper, recently published in the journal Sports Medicine, have found that, if anything, exercising in the evening might even confer a slight edge in terms of time spent in deep sleep.
The type of exercise performed in the evening does matter, however – one of the studies included in the review suggested that vigorous exercise (defined as a physical activity where a person is unable to talk) increases the time it takes to fall asleep, likely because of insufficient time to get back to one’s resting heart rate.
According to Jan Stutz, a co-author on the study, and doctoral student at the Institute of Human Movement Sciences and Sport at ETH Zurich, these findings could be useful for people who don’t have enough time to exercise during the day and fear that evening physical activity will hamper their pillow time.
“People can do exercise in the evening without hesitation. The data shows that moderate exercise in the evening is no problem at all.” Adverse sleep effects from light to moderate exercise were absent in all 23 of the reviewed studies.
A point of caution raised by the authors is that even though they couldn’t find any evidence to back up the idea that physical activity close to bed is detrimental to sleep, everyone’s body reacts to exercise differently, so monitoring how one does with working out at different times of the day is still warranted.
The catch-all myth that exercise should always be done during the day, on the other hand, is pretty much busted. “It is well known that doing exercise during the day improves sleep quality,” said Christina Spengler, head of the Exercise Physiology Lab at ETH Zurich. “Now we have shown that, at the very least, exercising in the evening doesn’t have a negative effect.”