Sleep has a big impact on learning. And not just when you do it in class. Sleep deprivation affects memory, cognition and motivation, and the effects are compounded when it's long-term.
For those reasons, there's been lots of interest in the education world in studying the sleep habits of children and adolescents. But until now, most sleep studies have been limited to short-term surveys with small numbers of participants.
That's changing with the advent of wearable activity trackers. These devices include an accelerometer that detects movement and tries to decide whether you are running, sitting or sleeping. They can't directly measure whether people are asleep, so experts say they're not as accurate as hooking someone up to machines in a lab.
But they are worn by large numbers of people in the real world, who voluntarily grant companies like Jawbone the ability to gather lots and lots of data.
Jawbone, the maker of a tracker called UP, has just released a study of the sleep habits of tens of thousands of students, ages 18-22, on college campuses. The information comes from 100 universities, totaling 1.4 million nights of sleep.