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How to Get A's, Not Zzzz

Schools Are Trying to Adjust Hours to Teens' Inner Clocks


This is how 17-year-old Natalie Kepes starts every school day: 6:30 a.m., buzzzzzzz goes the alarm clock--and slam goes her hand on the snooze button. Buzzzzz, slam. Buzzzzz, slam. Then . . . 7 a.m.? Yikes! No more snoozing.

She gets dressed, grabs something to eat and makes a mad dash to El Camino Real High School in Woodland Hills. But she's still not really awake when class starts at, ugh, 8 a.m. Maybe her first-period teacher will let her doze a few minutes. Maybe . . . not.

Teenagers--what undisciplined slugs! If they'd only get to bed earlier, waking up in the morning wouldn't be such an ordeal. Right?

Parents and even sleep experts have long thought so, believing that adolescents deliberately drag out bedtime and hate getting up because of pubescent rebellion and other social factors.

But science is proving otherwise.

Leading sleep researchers are coming to the conclusion that teenagers' inner clocks, their circadian rhythms, are set differently from the ones that govern slumber patterns in the rest of us. They have come to this conclusion by scrutinizing teenagers' sleep cycles, even isolating them in laboratories to measure their levels of melatonin, the brain hormone that regulates sleepiness. And they are finding evidence that teenagers have a physiological need to go to bed and wake up later than most of the rest of us--a phenomenon called "phase delay" in sleep lingo.

This research led the Minneapolis school board in May to postpone the start of middle school by 2 1/2-hours, to 9:40 a.m., and high school by one hour, to 8:40 a.m.

"From the age of 14 to 18 or 19, kids' sleep patterns are just different. The evidence is there," said Kyla Wahlstrom, associate director of the Center for Applied Research and Educational Improvement at the University of Minnesota.

To be sure, some kids have no problem rising with the sun. And for some of those who find it painfully hard, simple sloth may be the reason. But research suggests that biological patterns are the main culprit for many teenagers.

"We don't have the final answer yet. But we have some hints," said Mary Carskadon, a Brown University professor of psychiatry and human behavior, "that there is a change in the circadian timing mechanism that favors this delay."

About 20% of all high school students sleep in school, according to a 1995 study. Difficulty waking up is a prime cause of school tardiness. At Monroe High School in Sepulveda, school workers take the problem seriously enough to send 6:30 a.m. wake-up calls to chronic over-sleepers.

Contrary to popular belief, experts say, teens need more shut eye--about 10 hours a night--than grown-ups and younger children. But most get only six or seven hours a night as a number of factors conspire against them: More high school kids need to work after school or take care of younger siblings. And the high school day is starting earlier than it used to. Monroe, for instance, moved up the start of class by 15 minutes last year, to 7:45 a.m., when it adopted a year-round schedule to relieve campus crowding.

Getting Less Sleep When It's Most Needed

Therefore, teenagers are getting less sleep when their bodies most need it. So, many walk around like zombies.

"We need more sleep," said Kepes, who is so sleep-deprived during the week that she snoozes 12 or 13 hours straight on weekends to catch up.

Carskadon and Amy Wolfson, a psychology professor at College of the Holy Cross in Worcester, Mass., found in a 1996 study of 3,120 Rhode Island high school students that 85% were getting insufficient sleep--less than 8 1/2 hours a night during the week. On weekends, the majority went to bed later and got two hours more sleep.

Similar findings were reported by Richard P. Allen and Jerome Mirabile of the Sleep Disorders Center at Johns Hopkins University, who examined 61 Maryland high school students in 1989. Those students got about seven hours of sleep on weeknights, with bedtimes close to 11 p.m. On weekends, with fewer constraints on their schedules, they slept about nine hours a night, despite bedtimes as late as 2 a.m.

The Maryland students also reported that on school days they felt least alert at 10 a.m. and most alert after 3 p.m. This could be due to boredom with school, of course. But Allen said the weekend sleep lag is strong evidence that something else is at play, a biological timekeeper that makes getting up at 6 a.m. for teens as abhorrent as 3 a.m. would be for adults.

Not surprisingly, Allen and Mirabile found a correlation between getting more sleep and higher grades. Similarly, Wolfson and Carskadon found more depression, lower grades and behavioral problems among students who got less than the recommended nine or 10 hours a night.

Allen said the evidence isn't strong enough yet to establish a cause-and-effect relationship between sleep time and achievement, "but there is enough circumstantial evidence to suggest that moving high school an hour later is a good idea."

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