How people sleep in different countries (Courtesy of Science Advances)
A sleep study published in the May Science Advances offers new insights into how people sleep in different countries. Subjects used a simple, free smartphone app called ENTRAIN to report their sleep habits in the real world rather than in a laboratory. Five thousand people took part in the study.
ENTRAIN asked users for usual sleep times, home time zone, typical lighting as well as basic information such as age, gender and country. The app also can record hourly light and sleep schedules, as well as jet lag experienced by participants. Through mathematical modeling and statistics, researchers found that people in Singapore and Japan get the least sleep, while theDutch and New Zealanders sleep the most. The study also revealed that women generally slept more than men, going to bed earlier and waking up later.
Users who reported being exposed to outdoor light during the day also tended to go to sleep earlier and sleep more, compared to those who spent most of their day in an office under artificial lighting. Finally, the study showed that age is the primary determinant of sleep timing.