A Matter of Timing


Amira Hamlet doesn’t trust her alarm clock. She knows she’ll sleep right through it. So at 6:30 a.m., the 18-year-old has her mom rouse her out of her deep slumber. Then she hopes a blast of water from the shower and a good 20-minute dose of rockin’ MTV will pry her eyes open before she jets off to Rio Mesa High School by, ugh, 8 a.m.

Staying awake during the morning hours has always been an ordeal for this Oxnard teen, and she’s a valedictorian. “It takes me until second period to wake up,” she said. “I have to force myself to wake up. I’m just half there.”

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.

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 High School in North Hills, for instance, made the start of class 15 minutes earlier last year--7:45 a.m.--when it adopted a year-round schedule to relieve campus crowding.

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

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, most 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 getting 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.”


Many educators scoff at such findings, convinced that early-rise schedules help teenagers adjust to real-world demands.

Rio Mesa High School counselor Kristopher Wong ascribes to the early-to-bed concept. “When they get to sleep at 10 p.m., they are OK,” he said.

In Minnesota, though, students and administrators say they have positive proof that starting school later makes a difference.

At Edina High School, in a Minneapolis suburb, the start of school was delayed an hour last fall, from 7:25 to 8:30 a.m. Doug Aamoth, 17, said he still goes to bed at the same time--between 10 and 11 p.m.--but is able to sleep an hour later in the morning. That extra hour, he said, has made a tremendous difference.


“Last year, I’d wake up, say ‘OK, second hour we’re not doing anything, so I can sleep.’ It was a constant struggle.” His grades have improved now, because he’s “paying attention, not sleeping.”


Edina Principal Ronald Tesch said delaying the start of the high school day caused consternation at other schools because bus routes and schedules had to be changed. Athletic coaches feared the later ending time would cut into practice sessions.

But the benefits appear to be outweighing the drawbacks. Teachers are reporting that students are more alert in class. Attendance has improved and tardiness declined.

“I don’t know anyone who doesn’t like the later time,” said senior Aarthi Belani, 17. “It’s a lot more natural.”

Correspondent Regina Hong contributed to this story.