You’ve heard me say
exercise is good for sleep. Research has documented the benefits
of exercise to improving sleep patterns. Exercise lifts mood
and reduces stress. It can strengthen
circadian rhythms, promoting daytime alertness and helping bring on sleepiness
at night. Exercise has been shown to improve sleep for people with sleep
disorders, including insomnia
sleep apnea. A recent National Sleep Foundation poll found that regular
exercisers were significantly more likely to report sleeping well on most
nights than people who were not physically active. Research has shown exercise
can help to improve not only the quantity of sleep but also the quality: studies
daytime physical activity may stimulate longer periods of slow-wave sleep, the
deepest and most restorative stages of sleep.
new study takes
a closer look at the relationship between exercise and sleep.
confirm some of what we already know: a regular exercise routine does
contribute to improved sleep. But this research also sheds some light on the
complexity of the relationship between sleep and exercise. In particular, the
study suggests that exercise may not have an immediate impact on sleep, but in
fact may take several weeks or months to significantly change sleep. Sleep, on
the other hand, may have a very short-term effect on exercise. According to
these results, a poor night’s sleep can have a negative effect on next-day
Researchers at Northwestern University’s Feinberg School of
Medicine investigated the bi-directional
relationship between sleep and exercise, studying not just the effects of
exercise on sleep, but also the effects of sleep on exercise. They used data
from an earlier sleep
study that examined the impact of moderate, regular physical activity on
sleep, mood and quality of life among a group of adults 55 years and older, all
of whom had chronic insomnia. None of the subjects exercised regularly.
Researchers divided the subjects into two groups. One group remained with their
sedentary routine, while the other group began a regular exercise program that
included 3 to 4 30-minute sessions per week of moderate aerobic exercise. After
16 weeks, the exercise group had improved sleep significantly and across
several measures of sleep, including sleep duration and sleep quality, as well
as daytime sleepiness. The exercisers also reported improvements to their moods
and to their quality of life.
For the current study, researchers looked closely at this
data, this time to see how quickly exercisers saw improvements to their sleep.
They wanted to know whether individual daytime exercise sessions led to better
sleep later that same night. They also investigated what impact sleep had on
exercise the following day. Their analysis revealed that though exercise did
have a significant positive impact on sleep, its effects were not immediate:
exercise sessions did not have an immediate effect on sleep. Researchers
found no improvements to sleep from exercise on a day-to-day basis.
- As far
as 2 months into the 16-week study period, the exercising group had
experienced no significant improvements to their sleep. By the end of the
16 weeks, however, the exercising group had seen their sleep quality and
sleep quantity rise significantly.
exercise did not appear to have an immediate impact on sleep, analysis
showed that sleep did have an immediate—and significant—effect on
exercise. Subjects had shorter exercise sessions after nights when they
slept poorly. This relationship of poor sleep to diminished exercise was
strongest among subjects whose sleep was the most challenged at the
beginning of the study period.
This news might seem disappointing, especially for those
people who hoped that exercise might provide a quick fix for sleep problems.
But there are a few important points to keep in mind. First, this study did
confirm that exercise can have a dramatic effect on sleep. Exercising subjects
in the 16-week study eventually wound up sleeping as much as an additional 1.25
hours per night more than their non-exercising counterparts. If you’re not a
regular exerciser and you’re looking for a way to improve your sleep, starting
a routine of moderate physical activity is a great strategy. Just keep in mind
that the effect may happen gradually, not all at once. This is how we think of
exercise as applied to weight loss—and we may need to think of exercise in
relation to sleep the same way.
For those already exercising, terrific! Your regular
workouts are helping to protect the quality of your sleep. This study shows how
your sleep can protect and enhance your workouts. You can strengthen your
exercise regimen by getting a good night’s rest. That’s something to think
about before staying up into the wee hours to work or watch late-night
As we so often learn, there is no magic bullet or quick
fix to solve sleep problems. But when it comes to sleep and exercise, there is
a significant benefit to be gained by sticking with a regular routine, and
allowing the benefits to develop gradually. Slow and steady wins the race, in
Michael J. Breus, PhD
The Sleep Doctor®
Everything you do, you do better with a good night’s sleep™
twitter: @thesleepdoctor @sleepdrteam
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