Sleep Is One Thing Missing in Busy Teenage Lives

By DENISE GRADY

t 6:30 in the morning, a strapping teenager on the cusp of manhood can look an awful lot like a newborn puppy, with eyes that won't open and a powerful instinct to curl up under something warm.

Is this the same person who swore he wasn't tired at 10:30 the night before while he traded instant messages with six different friends at once, and who will probably do it again tonight?

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Parents know the adolescent drill all too well: stay up past 11 or 12 on school nights, stagger out of bed at 6 or 7, shower interminably, eat a token breakfast and bolt. Yawn through school, perk up for sports or clubs, fight sleep while doing homework. Come to life at 9 p.m., deny fatigue and stay up well after parents have collapsed into bed. Holidays and weekends, stay up half the night and then "binge sleep" until noon or beyond. Sunday night, restart the cycle of late to bed and early to rise.

Americans are said to be a sleep-deprived people, and teenagers are the worst of the lot. Most are lucky to get 6, 7 or 8 hours of sleep a night, even though studies have shown repeatedly that people in their teens and possibly even early 20's need 9 to 10 hours. Many live in a state of chronic sleep deficit that can affect mood, behavior, schoolwork and reaction time.

Dr. Mary Carskadon, a sleep researcher at Brown University, describes sleep-deprived teenagers as existing in a "kind of gray cloud."

"We just ignore these bad feelings from not enough sleep and get used to it," she said. "We forget what it's like to feel good, and how much more efficiently you can do things." Physical, emotional and social factors seem to conspire against letting adolescents get enough sleep.

When teenagers insist that they are not tired at 9 or 10 p.m., they are very likely telling the truth. For reasons that are not fully understood, Dr. Carskadon said, their body clocks shift, so that their natural tendency is to stay up later at night and wake up later in the morning than when they were younger. But that inner clock often clashes with the outer world: early starting times in high school and demanding schedules of sports, clubs, music lessons, homework and part-time jobs.

There are consequences. For one thing, lack of sleep can interfere with learning: tired students have a hard time paying attention, and even if they do somehow manage to focus, they may forget what they were taught because memory formation takes place partly during sleep.

In "Adolescent Sleep Patterns," a book published in August and edited by Dr. Carskadon, she wrote, "The students may be in school, but their brains are at home on their pillows."

Tired teenagers can be as cranky as tired 2-year-olds, and even less fun to deal with. More seriously, sleep deprivation can bring on feelings of stress, anger and sadness.

Dr. Carskadon said studies had repeatedly linked sleep deprivation to depressed mood — a temporary case of the blues, not the same as clinical depression.

"In every study where we've looked at it, it's crystal clear that kids who sleep less report more depressed mood," she said.

In one experiment, Dr. Carskadon said, teenagers were shown various photographs, and a researcher gauged their emotional reactions.

"Kids not getting enough sleep are less likely to respond in a positive way to positive things in the environment, and more likely to respond in a negative way to negative things," she said.

Pictures that most people would enjoy — images of cute babies, or of swimmers playing in waterfalls in Hawaii — do nothing for tired teenagers. "They're flat in their response," Dr. Carskadon said. "They don't say they felt pleasure. But if they see something negative, like a pizza with a big roach on it or a picture of the most disgusting toilet, kids who are sleep deprived sort of have a worse response. It makes them more angry than the kids who have had plenty of sleep. How does it translate into their real lives? We're not sure."

In her book, Dr. Carskadon noted that studies in animals showed that sleep loss was associated with "marked increases in aggressive behavior and violence."

Lack of sleep may take its toll physically as well. Growth hormone and sex hormones are secreted during sleep, but it is not known whether missing out on sleep disrupts hormonal patterns. Studies have shown that sleep deprivation may also diminish the body's ability to process glucose, and a prolonged sleep deficit can produce the kind of blood glucose levels found in people who are on the way to becoming diabetic.

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Studies in people and animals suggest that lack of sleep may also interfere with the working of the immune system and its ability to fight infections, but, Dr. Carskadon said, it is not clear whether sleep loss is linked to illness in people.

Lack of sleep also increases teenage drivers' already elevated risk of car accidents. According to the National Sleep Foundation, a nonprofit group, drowsiness or fatigue play a role in 100,000 traffic crashes a year, and drivers 25 or under cause more than half of those accidents. Sleep loss and drinking are an especially bad combination because fatigue greatly magnifies the effects of alcohol, according to a report by the sleep foundation.

Many health experts, and parents, say that high school starting times — often before 8 a.m. — are largely to blame for students' perpetual exhaustion. According to a poll in August by the sleep foundation, 80 percent of the people surveyed said high schools should not start before 8 a.m. The foundation favors 9 a.m.

Some school districts have already changed their schedules so that high school classes start later, between 8 and 9, instead of before 8. In some cases, the changes came about only after parents campaigned for them.

In Minnesota, the state medical association took a stand, and wrote school superintendents a letter warning that early start times were incompatible with teenagers' body clocks, and bad for health, school performance and driving. In 1996, Edina, Minn., a suburb of Minneapolis, changed its high school starting time from 7:25 to 8:30, and in 1997, Minneapolis changed high school opening times to 8:40 from 7:15.

Researchers from the University of Minnesota have been studying the changes and report that, for the most part, students and teachers prefer the later start times. Many parents now want middle school to start later as well. Teachers say students are less likely to fall asleep in morning classes, and some students say they get more sleep and are more likely to eat breakfast. Suburban schools say students behave better, and in the city schools, attendance and graduation rates have gone up and tardiness has decreased.

The drawbacks are that some students, especially in city schools, are unable to take part in after-school activities, and some say they are earning less at their after-school jobs.

But not all school districts are willing or able to alter their schedules because they do not have enough school buses to carry children from elementary, middle and high school during the same hours. Some have concerns, too, that later schedules will interfere with after-school sports.

According to the sleep foundation, individual schools and districts in 13 states have changed to later school start times. But many still start before 8 a.m., and nearly all before 9. A few schools are starting earlier.

The military has shown more flexibility than some school districts. Concern about sleep deprivation led the United States Navy last April to change the "rack time," or sleeping hours, for young sailors — many of whom are in their late teens — at the Great Lakes base in Chicago, where all basic training is done.

Previously, the schedule allowed only six hours of sleep, from 10 p.m. until 4 a.m. The Navy first tried adding one hour by ordering lights out at 9 p.m., but psychologists who had studied sleep said that was the wrong approach.

"I toured the barracks after lights out, and found what we expected," said Dr. Jeff Dyche, a naval lieutenant and psychologist. "The recruits were lying in their racks staring at the ceiling. You can't force these kids to go to sleep that early."

Dr. Dyche said he and other psychologists briefed a three-star admiral about sleep research, especially Dr. Carskadon's work. The psychologists said young people could not fall asleep early and were at their sleepiest from 4 a.m. to 6 a.m. They recommended letting the recruits sleep later rather than ordering them to bed earlier, and allowing them eight hours of sleep a night.

The admiral agreed, noting that his generation had slept eight hours during training. He made the rack time 10 p.m. to 6 a.m.

Navy researchers are studying the soldiers to see if the extra sleep makes a difference.

"They're looking at test scores, sleep patterns, sick call and the number of times these kids get into trouble," Dr. Dyche said. "We want to compare it to years past and see what we get." Although the data are not in yet, he added, he expects "big dividends."

Doctors and sleep experts say parents need to play a stronger role in helping their teenagers to get more sleep.

Among the suggestions are setting a bedtime on school nights, being there to enforce it, and not letting the weekend hours drift so far out of line that they throw off the rest of the week.

Part of the strategy also includes limiting or banning television on school nights, as well as telephone and Internet socializing.

The intentions are noble, but perhaps not so easy to carry out, especially at 11:30 when the 15-year-old needs "just a few more minutes" to finish an English project or practice a solo for the next day's concert.

But it may be that a good night's sleep, given a chance, will sell itself. Dr. Carskadon said that one young man, who slept nine hours a night for a week as part of a study, told her: "You know, this is really good. I might try this even when the study's over."