A teen's relationship — or lack of good relationship — with parents, pals or teachers may have a lot to do with why most kids aren't getting the nine to 10 hours of sleep that doctors recommend. The hormonal disruptions of puberty likely also play a role.

That's the word from David Maume, a sociologist and sleep researcher at the University of Cincinnati. Maume recently analyzed federal health data from a survey of 974 teenagers who were questioned first when they were 12 years old, and then again at age 15. His findings appear in the December issue of the Journal of Health and Social Behavior.

Teens who had very warm relationships with their parents — who said they felt supported, for example, and could talk to their folks — tended to sleep better, Maume found. "Whereas, families going through distressful times — divorce or remarriage — that tended to disrupt teen sleep," he says.

Having problems or feeling unsafe at school also disturbed sleep, though students who said they had good relationships with teachers tended to sleep better.

Teens who reported having strong friendships with peers who shared similar academic goals, or who were involved in sports or other school activities also got a better night's sleep.

Kids, it turns out, aren't so different from adults in this way. "If we're happy and content," Maume says, "we're much more likely to sleep better than if we're distressed and anxious and worried."

Of course, teens are often more drawn to their computers and social networking than adults are. But Maume found that when parents were strict not only about bedtime, but also about limiting technology, the kids slept better.

"It's a finding that seems obvious," Maume says. "But perhaps we need reminding that parents really do matter when it comes to health habits of their teenagers."

The national data suggest that, on average, kids lose about an hour and a half of sleep a night between ages 12 and 15 — dropping from about nine hours per night to a little less than eight.

Nudging that number back up to the recommended nine or 10 nightly hours seems impossible to Stacy Simera, an Ohio mental health therapist who is also mother to 14-year-old Graig.

"As a mom, my role is to set the right environment for my son," Simera says. "He does not have caffeine. He does not have TV in the bedroom, [and] no cellphone or iPad in his room when he's supposed to be asleep."

Graig's good about all of that, Simera says. But even if he hits the sack at 9 p.m., she'll often hear him tossing and turning until after 11.

Dr. Shalini Paruthi, who heads the pediatric sleep and research center at St. Louis University, blames the shifting hormones of puberty for throwing a wrench into the internal clock of many teens.

"They're not as sleepy as early as they used to be," Paruthi says. "So, in grade school they were easily going to sleep and getting sleepy at 8:30, [but] now they're getting sleepy at 9:30 — and for some kids it goes much further."

As with many hormonal changes, some people are more affected than others. But whatever the cause, statistics suggest that kids who don't get the ideal nine or 10 hours total of shut-eye each night are at higher risk for things like poor academic performance, colds, flu, depression and — among teens old enough to drive — accidents on the road.

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