Earlier Bedtimes Linked to Increased Physical Activity, Study Finds

A new study indicates that turning in earlier might help boost your physical activity the next day—even when your total sleep time remains the same. Published in the Proceedings of the National Academy of Sciences, the research also revealed that sleeping longer than usual was surprisingly associated with less activity the following day.

While the connection between sleep and physical activity is well established, researchers haven’t fully understood how these behaviors interact on a daily basis. “We wanted to cut through the noise and understand how average sleep and nightly changes in sleep are linked to physical activity the next day in real-life settings,” explained Josh Leota, PhD, study co-author and research fellow at Monash University’s School of Psychological Sciences.

The research team analyzed a year’s worth of sleep and movement data from 20,000 physically active adults using the WHOOP activity tracker. Their findings revealed several key patterns:

- Participants who went to bed earlier averaged more moderate to vigorous activity the next day. Specifically, those who turned in at 9 p.m. completed about 15 more minutes of exercise compared to people sleeping at the average bedtime of 11 p.m., and 30 minutes more than those with 1 a.m. bedtimes. The biggest activity gains occurred when individuals shifted their bedtime earlier by 1.5 to 3 hours, even if total sleep duration stayed the same.

- Paradoxically, people who slept less than seven hours actually reported more activity the next day, logging 17 to 30 more minutes of movement and up to 31 additional minutes of moderate to vigorous exercise compared with those who got seven hours. In contrast, getting more sleep than usual was linked to reduced activity the following day.

To confirm their findings, the researchers analyzed data from 6,000 FitBit users in the NIH’s All of Us Research Program, which captures health information across the U.S. population. The results were similar, reinforcing the main conclusions of the original study, according to Professor Christopher E. Kline of the University of Pittsburgh.

The researchers suggest that the boost in activity from earlier bedtimes is largely practical: people who go to bed earlier tend to wake up earlier, giving them more time and energy to exercise before daily obligations. Conversely, extra sleep can encroach on time available for physical movement, especially for those with busy schedules.

However, experts caution against routinely cutting back on sleep in hopes of squeezing in more exercise. The Centers for Disease Control and Prevention recommends that adults get at least seven hours of sleep per night for overall health. Instead, experts suggest gradually shifting bedtime earlier to create more opportunities for physical activity.

To shift bedtime, Professor Kline recommends minimizing evening bright light exposure and seeking out sunlight and exercise in the morning. For those who naturally have later bedtimes, incorporating scheduled activity into the day—regardless of timing—can help ensure exercise doesn’t get crowded out by other tasks or obligations.

In summary, the study highlights the potential benefits of aligning bedtimes earlier to help fit in more physical activity, reinforcing the intricate relationship between sleep habits and daily movement.