Sleep and physical activity are key to staying healthy, but how they affect each other over time isn’t fully understood. We know being active boosts health, so figuring out what influences activity, like sleep, could help us find better ways to encourage it.
A large study by Monash University, published in PNAS, tracked nearly 20,000 people wearing WHOOP fitness bands for a year, collecting over six million nights of sleep data. Researchers looked at how sleep length and timing affected how much moderate-to-vigorous activity participants did the next day.
Researchers found that both consistent sleep habits and night-to-night changes affect how much people move the next day. Going to bed earlier, especially around 9 pm, was linked to significantly more physical activity. These early sleepers recorded 30 extra minutes of moderate-to-vigorous movement daily compared to the night owls heading to bed at 1 am.
Even among people with typical bedtimes, those who regularly slept at 9 pm were noticeably more active, logging 15 extra minutes of moderate-to-vigorous physical activity daily compared to those with an 11 pm sleep time, the group’s average.
Dr. Josh Leota from Monash University notes that evening chronotypes may struggle under rigid 9-to-5 schedules. These mismatched routines can lead to “social jetlag,” a disconnect between biological sleep timing and societal demands, resulting in poorer sleep and reduced energy the next day. Less motivation, more fatigue, and lower physical activity often follow.
The study also showed that people don’t have to change everything; just going to bed earlier than usual (while still getting the same amount of sleep) helped them be more active the next day.
Dr. Leota suggests health campaigns should combine sleep and activity advice, encouraging earlier bedtimes to naturally promote movement. Understanding how sleep and exercise work together could lead to healthier communities.
Senior researcher Dr. Elise Facer-Childs emphasizes a strong link between when you sleep and how active you are the next day. While both sleep and exercise are known to support good health, this study reveals they’re deeply connected in everyday routines.
If you sleep earlier than usual but get the same amount of sleep, you’re more likely to be physically active the next day. This pattern held true across diverse groups.
Journal Reference:
- Josh Leota, Mark É. Czeisler, Flora Le, et al. Sleep duration and timing are associated with next-day physical activity: Insights from two large-scale wearable sensor studies. PNAS. DOI: 10.1073/pnas.2420846122
