Out-of-Whack Body Clocks Keep Teens Sleepy: Study

Sleepy high-school students slumped over their desks just can’t help it, CNN reports. Most school start times play havoc with teens’ circadian rhythms: Teens naturally go to bed later than adults, and need more sleep. A new study finds pushing the high-school start time from 7:30am to 8:30 increased the number of students getting 8 hours of sleep dramatically.

The experiment also led to a steep drop-off in car accidents involving teenagers, which the authors attribute to more alert student drivers on the road. The issue has picked up enough steam that the Centers for Disease Control is recommending schools amend schedules given the “deleterious impact of school times on our teenagers.” And there’s nothing they can do about it. “It's biological, mediated by melatonin,” one study author said. (More high school stories.)