There’s a link between your workout and your sleep
When exercising late at night, it’s best to wind down a little before hitting the sack
Sleep: It’s a precious commodity and one of the pillars of health and wellness. But for about onethird of Canadians, sleep doesn’t come easily, which makes everyday tasks, including exercise, that much harder to enjoy.
Yet despite the seeming contradiction in using exercise to battle fatigue, working up a sweat is often suggested as a first line of defence for those who have trouble sleeping. Several studies have shown that regular physical activity improves sleep habits, including reducing the time it takes to get to sleep, increasing total time spent sleeping and improving sleep efficiency (the percentage of time spent asleep while in bed). Even a single bout of exercise has proved to have a positive effect on quantity and quality of sleep.
Sleep experts aren’t sure why exercise helps, but the most common theory is that a postworkout drop in body temperature induces drowsiness. There’s also the theory that exercise’s positive effects on mood, stress and the body’s circadian rhythms make it easier to get the recommended seven to eight hours of sleep a night.
But it’s not all good news. Fitness enthusiasts have long complained of struggling to wind down after an evening workout, making it harder to get to sleep. And whether it’s due to the stimulating effect of exercise, residual muscle soreness, elevated heart rate or body temperature, evening exercise has a reputation for spoiling a good night’s sleep.
Despite these complaints, studies measuring the effects of latenight exercise on sleep haven’t been definitive. Part of the problem is the variability in study design, which makes it difficult to compare results. Some use subjects with pre-existing sleep problems, while others measure the effects of exercise on otherwise good sleepers. Many also fail to address the difference that variables like exercise intensity and duration may have on sleep.
In an effort to make sense of the wealth of data out there, a group of Swiss researchers searched 11,717 studies based on the effect of a single session of evening exercise on sleep. They settled on 23 good-quality studies that included a total of 275 study subjects.
All but one of the studies featured healthy exercisers, ranging from sedentary to trained athletes, with healthy sleep habits. The most common forms of exercise were running and cycling, with subjects working up a sweat for an average of 87 minutes, 12 minutes to four hours before bedtime (the average was 1.8 hours before bed).
The results suggest that evening exercise isn’t likely to be the cause of persistent tossing and turning when the lights go out — though there is a caveat.
“Overall, the studies reviewed do not support the hypothesis that evening exercise negatively affects sleep; rather, if anything, the opposite was the case (although the effects were small), with one potential exception: with intense exercise very close to bedtime, time to sleep, sleep efficiency and total sleep time might be impaired,” the researchers said.
Interestingly, the main consequence of a tough workout before bedtime is taking too long to get to sleep, but once sleep comes there’s little, if any, disruption until morning.
Also worth noting is that fitness novices and fanatics differ little when it comes to being able to sleep after exercise.
As interesting as the results are, there are still plenty of unanswered questions for those who struggle getting to sleep after an evening workout. Is swimming or yoga a better option than a game of hockey or basketball? What’s the ideal time frame between the end of a workout and bedtime? Does age play a role?
Finding out more about how late-night exercise affects sleep is important, as a good portion of the population pulls on workout gear after 5 p.m. Common sense suggests that the greater the gap between exercise and hitting the sack, the better the chance of dozing off. But for those who have little choice but to do their workout closer to bedtime than mealtime, it might be a good idea to find a way to wind down before turning in for the night.
Avoid screen time, which has been proven to disrupt sleep. Instead, establish a post-workout ritual such as taking a hot shower or listening to music or an audiobook. If that doesn’t work, consider changing your workout to something less intense, like an evening walk or yoga class, saving more vigorous workouts for earlier in the day or evening.
The bottom line is that exercise should be a sleep aid, not a deterrent, so time your workouts accordingly.