Physical activity is well known to be associated with healthy sleep, but a new study hints that some types of physical activity might be better than others.
The study showed that physical activities, such as walking, as well as aerobics/calisthenics, biking, gardening, golfing, running, weight-lifting, and yoga/Pilates, are associated with better sleep habits compared with no activity.
In contrast, physical activity that involved household and childcare is associated with poor sleep habits.
“My feeling is if you are getting most of your physical activity from household work and childcare, you have other problems, you have stress, time demands, and that’s why you aren’t sleeping,” Michael Grandner, PhD, instructor in psychiatry and sleep researcher at University of Pennsylvania Perelman School of Medicine in Philadelphia, noted in an interview with Medscape Medical News. He presented the findings at SLEEP 2015: Annual Meeting of the Associated Professional Sleep Societies.
The researchers analyzed sleep and physical activity data from the 2013 Behavioral Risk Factor Surveillance System for 429,110 adults. Survey respondents were asked what type of physical activity they spent the most time doing in the past month, as well as how much sleep they got in a typical 24-hour period. Sleep time was characterized as very short (≤4 hours), short (5 to 6 hours), normal (7 to 8 hours, reference), and long (≤ 9 hours).
Compared with those who reported no physical activity in the past month, walking was associated with a decreased likelihood of very short sleep (odds ratio [OR], 0.59; P < .0001), short sleep (OR, 0.83; P < .0001), and long sleep (OR, 0.76; P < .0001).
Compared with just walking, aerobics/calisthenics, biking, gardening, golf, running, weight-lifting, and yoga/Pilates were each associated with decreased likelihood of insufficient sleep, while household/childcare activity was associated with higher likelihood of insufficient sleep. The results were adjusted for age, sex, education level, and body mass index.
“Walking alone has a big effect,” Dr Grandner told Medscape Medical News, “but some exercises seem to give an added bonus above walking on sleep time and they include aerobics/calisthenics, biking, yoga, golf, running, weight-lifting.”
While this study suggests that “what you do may matter, the take-home message is do something rather than nothing,” Dr Grandner said. “People who get physical activity are less likely to be short sleepers than people who don’t get activity. Active people are more likely to be getting the recommended amount of sleep.”
The study doesn’t say anything about sleep quality, he noted. “We can’t say, do this activity and your sleep will be better, but we can say that the people who are doing this are more likely to be getting the recommended amount of sleep.”
Listen to Your Grandmother
“This is a correlation study and you can never prove causality, which the authors note,” Saul Rothenberg, PhD, behavioral sleep psychologist, North Shore-LIJ Sleep Disorders Center in Great Neck, New York, noted in an interview with Medscape Medical News.
“What’s difficult to interpret with this kind of study is what is leading what. The most likely assumption is that the people who engage in more vigorous exercise are more health conscious and are more likely to want to get a good night sleep. You could argue that people who get less sleep tend to have less energy to engage in engage in those kinds of more energy-demanding forms of exercise, so there is a lot more to learn about this,” said Dr Rothenberg, who wasn’t involved in the study.
What’s also “really important,” he said, is that “health conscious people are starting to value getting the right amount of sleep. Although it’s shocking to me how many people think that getting 6 hours of sleep is okay and good, when it turns out that two thirds of adults need between 7 and 9 hours.”
In any event, “Your grandmother’s idea that in order to get a good night sleep you needed to have a full day of activities is not so far off,” Dr Rothenberg said. “What you do during the day does matter and it appears if you fill your day with lots of activities it does appear that you’ll get a better night’s sleep. The demand from the daytime activities seems to produce better-quality sleep.”