SSS 2010-07-05

（单词翻译）

Teachers get exasperated¹ 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 adolescence², 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, depressed³, annoyed or irritated dropped significantly.

Before the study, teachers, coaches and administrators⁴ 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