There are many, many perfectly good excuses for not exercising.
I’m too full from lunch. I’m too hungry before dinner. I don’t have time in the mornings. I’m too busy during the day. We can find all kinds of reasons to avoid getting the physical activity we all know we need.
Well, at least one popular excuse is officially off the table, at least for most of us. Turns out, exercising in the evenings and before bedtime does not cause sleep disturbances after all.
In fact, according to a recent scientific review of the extensive literature on sleep quality and exercise, if there is any effect it is slightly positive.
Debunking the widely held belief that avoiding exercise in the evenings can improve sleep quality, researchers from the Institute of Human Movement Sciences and Sport at ETH Zurich combined the data from 23 different studies to reach their conclusion:
“If doing sport in the evening has any effect on sleep quality at all, it’s rather a positive effect, albeit a mild one,” says Christina Spengler, head of the ETH Exercise Physiology Lab.
According to the analysis, the only type of evening exercise that may pose an issue for sleep quality is vigorous training within an hour before bedtime. Because test subjects weren’t able to recover sufficiently in the hour before they turned in, they weren’t able to fall asleep as quickly.
Vigorous training is generally defined as that intensity at which a person would be unable to talk while exercising, such as high-intensity interval training for competitive athletes.
Which means the vast majority of us still have no excuse.
If we are to follow the official recommendations of health physicians, we should be doing a minimum of 150 minutes of moderate exercise every week (20 minutes per day). While some prefer to squeeze in a session at the gym first thing in the morning, others may struggle with energy and time in the early hours before the work day begins.
The results of the scientific review means people can feel comfortable scheduling in a workout in the four hours before bed without worrying about negative sleep impact. As long as the exercise stays in the range of moderate (think dancing, walking briskly, running, jumping rope etc.), you’re unlikely to feel any disruption in your sleep quality, even if you finish within the hour before bedtime. If anything, you may find that your sleep quality actually improves, according to the studies.
Of course, there are always exceptions. The authors of the analysis point out that they reviewed averages only, which means they can only make general statements with regards to study results. As Jan Stutz, doctoral student in the research group and lead author of the analysis reminds us:
“Not everyone reacts to exercise in the same way, and people should keep listening to their bodies. If they notice they are having problems falling asleep after doing sport, they should try to work out a little earlier.”