Bedtime matters: earlier sleep boosts next-day activity, new study finds and it could reshape Thai health habits
A new large-scale analysis of wearable data suggests that when you go to bed may be more important for your activity levels the next day than how long you sleep. The study, which pooled data from two massive wearable projects covering more than 100,000 people, found a clear pattern: going to bed earlier was strongly associated with more moderate-to-vigorous physical activity the following day. In particular, a bedtime around 9 p.m. stood out as a sweet spot, with those going to bed three hours before midnight logging roughly 30 more minutes of active movement each day compared with those who went to bed around 1 a.m. Even modest shifts toward an earlier bedtime—like moving from 11 p.m. to 10:30 p.m.—were linked with higher next-day activity, independent of how long people slept.