Teens' Biological
Clocks Different -
Classes Should
Start Later
OTTAWA - Forget the late-night parties or midnight movies. Some Canadian researchers say biology may be the reason many teenagers don't get out of bed easily.
Adolescents appear to have internal clocks that run at unique rhythms out of whack with the rest of the world, according to a study sponsored by Health Canada.
The preliminary results of the survey, believed to be the first of its kind in the country, suggest many teens have a natural wake-up time that goes off between 9 a.m. and 10 a.m. -- well after classes are already underway.
The same students also have a natural sleep pattern that starts between 1 a.m. and 2 a.m.
Teenagers not only drift off to sleep later than most adults, their bodies also require more sleep, researchers say.
The study is consistent with U.S. research, which suggests teenagers sleep odd hours because of puberty and hormones. American studies found that melatonin, the hormone that helps regulate the body's sleep cycle, is secreted at different times of day in teenagers compared with adults and younger children.
About 2,200 Ontario high school students were surveyed in the Health Canada research.
Although the results are still being analyzed, preliminary findings suggest high school students would be better off if classes were pushed back an hour or two.