Scientists Reveal Fitness Trick: Get More Sleep

As if you needed another reason to envy—or loathe—morning people. Research this week shows that people who go to bed early are more likely to be physically active than those who crave the night.

Scientists at Monash University in Australia led the study, which objectively examined people’s sleeping and exercise habits. Compared to late-night and typical sleepers, people who went to bed early tended to perform more physical activity the following day, they found. The findings also suggest that tweaking our bedtimes can indirectly help us stay more active, the researchers say.

“Going to sleep earlier than usual may be an effective strategy to maintain normal sleep duration while also optimizing next-day [physical activity],” the authors wrote in their paper, published Monday in the Proceedings of the National Academy of Sciences (PNAS).

Regularly getting a good night’s sleep and exercising are both vital keys to better overall health. But according to the researchers, it’s still unclear exactly how these two aspects of our lives can interact with each other. The team was particularly interested in finding out whether the timing of people’s sleep can affect their exercise time, too.

They analyzed data from two earlier studies that tracked people’s waking and non-waking activity via wearables. In the first study, roughly 20,000 participants wore an activity tracker for an entire year, meaning the researchers had data covering roughly six million nights of sleeping. Across the whole sample, people’s average bedtime was around 11 p.m. Early sleepers were classified as people who turned in for bed around 9 p.m., whereas late sleepers went to bed around 1 a.m.

Compared to late sleepers, early birds clocked 30 more minutes of moderate-to-vigorous physical activity on average, the researchers found; they also exercised about 15 minutes more than the typical sleeper. These patterns remained stable when the researchers analyzed data from the second study that involved almost 6,000 people who wore FitBits.

Though the study isn’t intended to answer why night owls might exercise less, the researchers have their educated guesses.

“Standard 9-to-5 routines can clash with the natural sleep preferences of evening types, leading to social jetlag, poorer sleep quality, and increased daytime sleepiness—which can all reduce motivation and opportunity for physical activity the next day,” said lead author Josh Leota, a scientist at Monash’s Sleep and Circadian Rhythms research program, in a statement from the university.

Our sleeping habits are influenced by many factors that aren’t easily adjusted, including the hours we work and our genetics. But there might be some hope for late birds who would like to exercise more. The researchers also found that people who slept earlier than their typical time, while still sleeping the same amount of hours as usual, tended to perform more physical activity the next day. In other words, it should be possible to work on our sleep and get more workout time all at once. And the researchers say that public health groups should try to emphasize both if possible.

“Rather than just promoting sleep and physical activity independently, health campaigns could encourage earlier bedtimes to naturally foster more active lifestyles. A holistic approach that recognizes how these two essential behaviors interact may lead to better outcomes for individual and community health,” said Leota.

I’m all for getting more beauty rest and gym time. But I will draw the line at 5 a.m. morning runs, just FYI.