We all know exercise is good for us. Good for our health, good for our waistlines, good for stress and for our clarity of mind. Exercise is also very -- very -- good for sleep. Research has shown that exercise can improve sleep, including for people with sleep disorders and other sleep-related illnesses. And now there's even more evidence of the sleep benefits that can come with regular physical activity.
The National Sleep Foundation devoted its annual "Sleep in America" poll to exploring the relationship between exercise and sleep. Their results found that people who exercise regularly experience better quality and more consistent sleep than those who do not. People who exercise are also significantly less likely to feel sleepy during the day, and to experience symptoms of sleep disorders such as insomnia and obstructive sleep apnea. And the news gets better: While more vigorous exercise is best, people participating in light exercise -- as little as 10 minutes of walking a day -- reported substantially better sleep than non-exercisers.
The NSF interviewed a nationally representative sample of 1,000 adults between the ages of 23 and 60. Participants were asked to report on their physical activity in the past week, providing details on the frequency, duration, and intensity of their exercise. They also were asked to report on the quantity and quality of their sleep, as well as sleep problems including symptoms of disordered sleep and daytime drowsiness. Participants provided information about their overall health, and personal habits including alcohol and smoking.
Based on the reports of physical activity, respondents were divided into four categories, according to their exercise habits:
- Vigorous: These people participated in activities like running, biking, swimming, and other pursuits that require significant physical exertion.
- Moderate: Respondents in this category spent time doing activities that included higher-than-normal levels of physical exertion, including yoga and weight training.
- Light: People in this category were physical active at normal levels of exertion, getting their exercise primarily by walking.
- No activity: The respondents in this category did not engage in exercise.
The results were striking. All respondents -- from vigorous exercisers to non-exercisers -- reported getting roughly the same amount of sleep on a nightly basis, an average of six hours and 51 minutes on workdays, and seven hours and 37 minutes on non-workdays. All groups also reported needing about the same amount of sleep to meet the demands of their daily lives: an average of 7 hours and 17 minutes. But exercisers at all levels reported sleeping substantially better than those who did not exercise:
- More than half of exercisers (56-67 percent) reported getting a good night's sleep every night or almost every night, compared to 39 percent of non-exercisers.
- Exercisers at all levels also reported higher quality of sleep than non-exercisers. More than three-quarters (76-83 percent) said their sleep was "very good" or "fairly good," compared to 56 percent of non-exercisers.
- More than half of exercisers at all levels also reported feeling their quality of sleep improve on days they engaged in physical activity.
While all exercisers reported significantly better sleep, the highest-quality sleep was reported by those who engaged in the most vigorous physical activity. Vigorous exercisers reported the highest sleep quality, and the most robust daytime energy levels. And they were least likely to have problems with their sleep:
- Twenty-six percent of vigorous exercisers said their quality of sleep was "very good," compared to 16 percent of light exercisers.
- Sixty-six percent of vigorous exercisers said they got more sleep than they needed, compared to 53 percent of moderate and light exercisers.
- Vigorous exercisers had fewer sleep problems than moderate and light exercisers, including less difficulty falling asleep and staying asleep, waking too early and not being able to fall back asleep. All exercisers reported fewer of these problems than people who did not exercise at all.
- Fifty percent of vigorous exercisers said they had no problems maintaining enthusiasm for the demands of their daily lives, compared to 40 percent of moderate and light exercisers and 33 percent of non-exercisers.
People who engaged in no exercise didn't just report lower quality sleep, they also reported in greater numbers a range of difficulties with their health and their daily lives:
- Non-exercisers were significantly more likely to say they experienced "very bad" sleep than exercisers. Fourteen percent of non-exercisers categorized their sleep as very bad, compared to 3-4 percent of exercisers.
- More than half -- 61 percent -- of non-exercisers reported "rarely" or "never" getting a good night's sleep on workdays, compared to 29 percent of vigorous exercisers.
- Non-exercisers were more likely to feel sleepy during the day. Nearly twice as many non-exercisers reported daytime sleepiness as exercisers.
- Daytime sleepiness interfered with non-exercisers daily activities and their safety more often than for those who exercised. Fourteen percent of non-exercisers reported having trouble staying awake while driving, eating, or engaging in social activity one or more times in the previous two weeks, compared to 4-6 percent of exercisers.
- Non-exercisers were significantly more likely to have symptoms of sleep disorders, including obstructive sleep apnea. Forty-four percent of non-exercisers demonstrated a moderate risk for sleep apnea, based on standard clinical indications for the sleep disorder. This number was more than twice as high as for vigorous exercisers, only 19 percent of whom indicated a moderate risk of sleep apnea.
The message here is clear: Put some time every day toward exercise, and when bedtime comes around you'll sleep better. For those trying to juggle a regular exercise routine amid busy schedules, there's some more good news in these poll results. The survey found that exercise at any time of day was good for sleep, including within four hours of bedtime. It's been a common recommendation -- including from the National Sleep Foundation itself -- to avoid exercise during the final four hours of the waking day, in order to prevent physical exertion from interfering with sleep. Based on these results, the NSF has revised its recommendation, and encourages normal sleepers to exercise at any time of day, provided that their exercise does not interfere with their sleep. People with insomnia and other sleep disorders should continue to schedule their exercise earlier in the day. And anyone who finds their sleep diminished by late-day exercise should do the same.
So, where do you fit in the sleep-exercise picture that these survey results illustrate? Are you sleeping as much, and as well, as you need? If you're looking for ways to improve your sleep, your daily exercise routine is a great place to start.
Michael J. Breus, PhD
The Sleep Doctor™
Everything you do, you do better with a good night's sleep™
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