SSS 2010-07-05（在线收听）

Teachers get exasperated at students—they don’t pay attention, they’re sleepy, they have bad attitudes. But improvement could be a matter of timing—just start school later. That’s according to a study in the Archives of Pediatrics and Adolescent Medicine.

Beginning at adolescence, kids have what’s called a delayed sleep phase, where they start sleep later and sleep later in the morning. And they need plenty—about nine-and-a-quarter hours a night.

The researchers evaluated 201 Rhode Island high school students whose school pushed back its start time from 8 to 8:30. The kids completed a sleep habits survey before and after the time change.

After the delayed start, the percentage of students who said they got at least eight hours of sleep a night jumped from about 16 to 55 percent. Class attendance improved, and there were fewer visits to the health center for fatigue-related complaints. Plus, the number of students who said they felt unhappy, depressed, annoyed or irritated dropped significantly.

Before the study, teachers, coaches and administrators all resisted the later start. After, nearly all voted to keep it in place. A half-hour change for happier, better students? Seems like a good time for all.

Thanks for the minute for Scientific American’s 60-Second Science. I’m Cynthia Graber