Taking more steps during the day may be related to better sleep at night, according to an encouraging new study of lifestyle and sleep patterns. The study, which delved into the links between walking and snoozing, suggests that being active can influence how well we sleep, whether we actually exercise or not.
Sleep and exercise scientists have long been intrigued and befuddled by the ties between physical activity and somnolence. To most of us, it might seem as if that relationship should be uncomplicated, advantageous and one-way. You work out, grow tired and sleep better that night.
But a variety of past studies indicate that the effects of exercise on sleep are more scrambled than that. In some studies, when people work out strenuously, they sleep relatively poorly, suggesting that intense exercise might disrupt slumber. Other experiments have found that the impacts of exertion and sleep work both ways; after a night of ragged sleep, people often report finding their normal workout extra wearing. Past research also has produced conflicting results about whether and how the timing of exercise matters, and if afternoon workouts aid or impair that night’s sleep.
Most of these past studies have focused on planned exercise, though, not more incidental, everyday physical activity, and much of the research has involved people with clinical sleep problems, such as insomnia. Little has been known about whether simply moving around more during the day, absent formal exercise, might influence sleep, particularly in people who already tend to sleep fairly well.
So, for the new study, which was published recently in Sleep Health, researchers at Brandeis University in Waltham, Mass., and other institutions decided to look into whether and how walking could be linked with sleep.
This study was part of a broader effort to encourage adults in the greater Boston area to be more active. For that initiative, researchers recruited 59 mostly middle-aged men and women in and around Boston who worked full time and were worried that they did not have enough time for physical activity. The researchers provided these volunteers with an activity monitor and, in some cases, suggestions about how to fit more walking time into their crowded schedules. (The study was, in part, testing the effects on activity of offering advice and encouragement versus only the monitor.)
The volunteers wore the devices for a month, tracking the number of steps they took every day and the number of minutes they spent moving in any way. Some of this activity was light, including housework.
The volunteers also completed a variety of questionnaires at the start and end of the four weeks and during each day of the study. Several of these concerned their sleep, asking them to rate its quality — such as how long it took them to fall asleep, how often they woke up, or how refreshed they felt the next morning — as well as its quantity, measured by when they reported going to bed and getting up.
For the current study, the researchers combed through the data for each of the 59 participants, focusing specifically on how much they had moved and how well they had slept, hoping to find discernible patterns.
They did. In fact, the relationships between moving and dozing turned out to be consistent and strong. In essence, the more steps people accumulated over the course of the month, the higher their self-rated sleep quality was during that time. Ditto when the researchers looked at the number of minutes they had spent moving; the more time someone was in motion during the month, the better they rated their sleep over all.
The linkages held even when the researchers drilled down to individual days. On any given day when someone had taken more steps than was typical for him or her, he or she usually reported better sleep quality that night. (There were few noticeable effects on sleep duration, since most of the volunteers already were sleeping about eight hours a night when the study began.)
“I think it’s fair to say” that these results indicate that people who move more also sleep better, says Alycia Sullivan Bisson, a graduate student in psychology at Brandeis, who conducted the new study with her adviser, Margie Lachman, and others.
And the activity required to see higher sleep quality was not daunting, she adds. The average step count among the 59 volunteers was about 3,000 per day, which is about a mile and a half of walking. Covering greater ground was associated with better sleep, but even among the least active, upping their mileage a bit on some days was related to better sleep later.
Of course, the links here between stepping and sleep are only links; this kind of observational study cannot prove that more walking causes better sleep. The experiment also was short-term, relied on people’s self-perceptions of how they slept, and was not set up to determine how, physiologically, walking affects the body and mind in ways that could later alter sleep.
But even with those caveats, those of us hoping for better shut-eye tonight, tomorrow and in the future might want to “incorporate more activity into our daily lives,” Ms. Sullivan Bisson says.
