Entrain is a free health app for Android and iOS that helps travelers fight off the dreaded jet lag and better adjust to new time zones. To do so, Entrain recommends custom schedules of dark and light, based on inputting your typical hours and then your destination. We’ve talked recently about how light exposure affects sleep in the context of Apple’s recent addition of Night Shift. The app is based on prior research on predictive models of light on circadian rhythms.

Researchers at the University of Michigan initially released the Entrain app several years ago, and asked users if they wanted to share their data. Roughly 8% of users elected to do so, and the results have now been published. Data was from thousands of respondents across the globe (exact number unavailable). Keep in mind these figures rely on user self-reported data, not actual sleep tracking given the design of the app.

Key findings included:

– Women reported more sleep than men
– Bedtime is related to society, while wake time is more linked to one’s internal clock (circadian rhythms)
– Those with later bedtimes reported less sleep
– People getting more outdoor light go to sleep earlier and sleep longer than people getting more indoor light
– Earlier bed times corresponded with older age
– Average sleep duration was shortest for residents of Japan and Singapore (7h, 24 mins), and longest for the Netherlands (8 hours, 12 minutes)
– Sleep schedules were most similar across global respondents for older individuals

This use of data derived from thousands of consenting smartphone users is interesting and demonstrates yet another use of mobile technology – not only for gathering a large study base, but also in its use of self-reported data. It would be great to see FitBit or other sleep-tracking apps and activity monitors release data on general sleep patterns across users worldwide. We recently discussed some interesting insights from the Pebble sleep tracker. In terms of numbers, though, that’s just the tip of the iceberg.

Source: University of Michigan

iTunes Link to Entrain