THURSDAY, Nov. 3, 2005 (HealthDay News) -- What turns early-to-bed children into nocturnal teenagers who often don't hit the pillow until close to midnight?
New evidence supports the idea that adolescent sleep patterns are a natural part of growing up, not a matter of laziness.
A team of American and Swiss researchers found that it takes longer for teens to need to sleep after being kept awake, suggesting they have an unconscious propensity to go to bed -- and wake up -- later. "This is another piece of the puzzle suggesting the need for later school times," said sleep researcher Dr. Robert Vorona, an associate professor of internal medicine at Eastern Virginia Medical School.
In recent years, both researchers and school officials have begun to pay more attention to the sleep habits of teenagers and younger children. Some schools have made start times later because of concerns that students are too sleepy to begin learning effectively at, say, 6:30 or 7 a.m.
Some sleep researchers suspect that teen sleep habits are closely linked to the physical effects of puberty and not a sign of sloth (as many parents still like to think) or of cultural influences such as late-night television. Indeed, an estimated 7 percent to 16 percent of teens suffer from a condition called "delayed sleep phase syndrome," which makes them want to go to sleep and wake up much later than other people; only a tiny percentage of adults -- fewer than one in 500 -- have the same problem.
In the new study, researchers from Brown University and the University of Zurich recruited six teenagers and seven children who either hadn't reached puberty or were in the early stages of it. Then they kept the students up for 36 hours to see how their sleep systems reacted.
The findings appear in the November issue of Sleep.
The research team found that it took longer for the older teenagers to need sleep. This suggests there is a "biological imperative in teens to have a later bedtime and wake time," said Vorona, who has reviewed the findings.
The authors rightly state that more research is needed because the number of subjects in the study is small, Vorona said. Still, he said there's plenty of evidence that teens need more sleep, and shouldn't be forced to wake up too early.
Many researchers believe teens require nine or more hours of sleep, but that can be hard to achieve when they're being squeezed by early school start times and late hours filled with homework, athletics, work and socializing.
"Inadequate sleep is problematic as it can impair academic performance, alter mood and increase the risk of motor vehicle crashes," Vorona said. "Parents should understand that their high school students need more, not less, sleep than is assumed for optimal performance. They may also want to encourage those in positions of power to reorient bus and school schedules to allow a later start and end time for high school students."
More information
The National Sleep Foundation offers tips on how teens can sleep better.
