Why some kids snarl in the morning: Their biology demands sleep

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Photo: 13-year old sleeping kidSchool has begun, and for many parents, that means reminding kids -- more than once -- to "Get out of bed!" Kids’ resistance to climbing out from under the covers isn’t simply adolescent irritability. Scientists say tweens and teens need about nine hours of sleep each night for good cognitive functioning -- so much so that the American Academy of Pediatrics recently recommended that middle and high schools delay their start times until at least 8:30 a.m.

“Doing so will align school schedules to the biological sleep rhythms of adolescents, whose sleep-wake cycles begin to shift up to two hours later at the start of puberty,” the AAP said in a statement.

A Colorado sleep researcher also advocates for later start times for tweens and teens, saying schools should start at 8:30 a.m. to give kids enough time for sufficient sleep. Lisa Meltzer, a professor of pediatrics at National Jewish Health in Denver, compared the sleep habits of 245 traditional students in grades 6-12 to those of 162 homeschool students. She showed that homeschooled teens get the sleep they need (generally waking at the time the other group of kids headed to school). That's in contrast to pupils who attend many public or private schools.

In Colorado, at least two schools -- Boulder and Fairview High Schools, both in Boulder -- have recently delayed their start times.

That homeschooled kids get more sleep may feel like an intuitive result, but Meltzer also found that homeschooled teens show fewer depressive symptoms than do the traditional students. Meltzer says the difference in environment may contribute partially to the difference in symptoms -- but that there is a significant correlation between depressive symptoms and sufficient sleep. Other studies of adults have shown a similar correlation.

Lisa Meltzer has been studying sleep for the last decade.

Other studies also show negative effects of insufficient sleep on kids, including increases in instances of asthma and weight gain.


  • Kids should dim lights at least 30 to 60 minutes before they go to sleep
  • If using screens for homework, use dark background with white text
  • Do computer work with sunglasses
  • Use less caffeine