Natalia Lusinski
Updated May 07, 2016 @ 3:30 pm
friends sleep
Credit: NBC

We’ve probably all experienced it at some point — jet lag and adjusting to a new time zone. After all, it’s a big world out there, full of different wake and sleep schedules — and maybe you’re better suited to a life in Spain, staying up until midnight (if you’re female) and just before midnight (if you’re male). Or maybe you prefer to go to bed early, around 10:30 p.m., like those in Belgium and Australia? What if there was an app to tell you which country you’re best suited for, as well as how you sleep in your home country?

Well, there is: the smartphone app ENTRAIN. And Olivia Walch, Amy Cochran, and Daniel Forger, mathematicians of the University of Michigan, did a study to help figure out where you should be laying your head (i.e., how you’re sleeping in your current country). The results were just published in Science.

The data came from ENTRAIN. In the study’s first year, in 2014, 8,070 people’s data was analyzed, and almost 2,000 more people joined the study in year two. All they (or you) have to do is put in the basics, like your country, time zone, age, gender, and when you get up and go to sleep. Also, it asks you for the lighting environment you’re in the most — bright or low indoor or bright or low outdoor.

“Light is the primary driving input to the circadian clock, and by recording your lighting history, we can simulate your body’s clock and make recommendations for behavior,” states ENTRAIN’s website. Plus, “There are differences in latitudes [which determine hours of sunlight], but they’re always engulfed by artificial light and culture,” said Walch.

Instead of studying sleep and wake habits worldwide, the researchers chose the 20 countries that input the most results. In case you’re curious, the “winners” were the U.S., Australia, Canada, the U.K., France, Spain, The Netherlands, Denmark, Germany, Belgium, China, Japan, Brazil, Switzerland, Singapore, Hong Kong, Italy, Finland, New Zealand, and the United Arab Emirates.

The study’s findings? Overall, women and girls got more sleep than men and boys by about 30 minutes. For instance, in the Netherlands, women get 8.4 hours of sleep per night, the study found, while men in Singapore averaged 7.3 hours.

As for when people went to sleep and woke up, it depended on age — i.e., little kids going to bed early and getting up early. Teens, though, went to bed later and slept in. (No surprise there, right? Those were the days…) The older the adults got, though, the earlier they went to bed and the earlier they got up. Belgium, Australia, and New Zealand had the earliest bedtimes, with the U.S. coming in fourth place. Americans also had the earliest wake times. But if you live in Spain or Sinapore, it’s another story — they went to bed last.

The more people that use ENTRAIN, the more helpful the app can be to us in the future, as well, the developers hope — including predicting one’s best bedtime and recommending ways to overcome jet lag when traveling out of their time zone.

Count us in! (After we download the app and get some sleep, of course.)

Want to test it out? Go here and input your sleep and wake times… and find out which country you belong in, or at least which one your sleep schedule suggests you belong in.

You can get the app here, and you can also watch a tutorial of how it works.