SAN ANTONIO - Joshua Knippel, 16, plays basketball at Lackland Air Force Base's Stacey Junior/Senior High School, and on game nights, he sometimes doesn't get to bed until close to midnight.
His school day starts before 8 a.m., making for some bleary mornings.
"No, I don't get enough sleep," he says. "I usually have caffeine drinks to stay awake. If I don't do that, I get very tired."
His mother, Vickie Knippel, says she tries to enforce an earlier bedtime, but with sports, homework and other extracurricular activities, it's hard to balance her three high schoolers' need for sleep with all they do.
"I notice that when they come home, they usually have to crash for a few hours before they can recharge and hit their homework," she says.
The Knippels are smack-dab in the middle of a national sleep drought among high schoolers. Sleep researchers say youths between 13 and 18 require 81/2 to 91/4 hours of sleep each night to function well and stay healthy.
"That's much more than teenagers realize they need, and dramatically more than they're getting," says Jodi Mindell, professor of psychology at St. Joseph's University in Philadelphia and author of "Take Charge of Your Child's Sleep" (Marlowe & Company; $15.95). "They're about two hours sleep-deprived, and that's a huge amount."
A biological shift
Part of the problem is biological, says Mindell. After puberty, a natural shift in teenagers' internal clock occurs, making it harder for them to fall asleep before 11 p.m., and pushing back the time they naturally wake up in the morning.
"It has nothing to do with laziness," says Dr. Paul Ingmundson, director of the Alamo Sleep Disorder Center in San Antonio. "It's a circadian phase delay that normally happens in the second decade of life."
But there are other cultural elements at play as well, say experts. Recent times have seen an explosion in "electronics in the bedroom" -- televisions, computers, video games, instant messaging, cell phones, iPods and other devices that stimulate teens late at night and steal sleep from them.
Add to that a roster of extracurricular activities and after-school jobs that push bedtime back.
"When I was a kid, when you came home from school you had dinner and never left that house again," says Mindell. "Those days are over." Some schools have preschool activities, notes Ingmundson, forcing some kids to get up as early as 4:30 or 5 a.m.
"That's pretty bad," he says.
On top of all this is a steep increase among teens in the use of caffeinated beverages and other products that only serve to keep them up at night.
Taken together, the culture that swirls around teens comprises a "perfect storm" guaranteed to rob them of needed slumber, says Dr. Judith Owens, head of adolescent medicine at the University of Colorado School of Medicine.
Wide-ranging side effects
And the health consequences aren't limited to teens who yawn during English class. A sleep debt carries all sorts of negative side effects. It affects teens' cognitive state, says Mindell, eroding their attention, memory, decision-making and problem-solving abilities, all of which are so important for learning during the day. Lack of sleep makes teens moody, irritable and cranky. It lowers their ability to handle frustration "and cope with the normal vicissitudes of life," says Owens.
A sleep debt makes teens more impulsive and likely to take risks -- characteristics with which teens already struggle. It corrodes "higher executive functions," says Owens -- an ability to anticipate consequences and reflect back on and modify behavior. Most distressingly, this lack of sleep is blamed for an increase in "drowsy driving" by teens. Mindell says about 100,000 vehicle crashes each year are a direct result of driver fatigue, and 55 percent of those crashes involve drivers 25 or younger.
Ironically, sometimes sleep deprivation among children and teens, with its attendant attention, concentration and behavioral problems, gets misdiagnosed as attention-deficit-hyperactivity disorder, says Ingmundson.
A stimulant is then given, making it even harder for the youth to get to sleep. So then a sleep aid is prescribed.
"It's like 'Alice in Wonderland,'" he says. "One pill to make you larger, one pill to make you smaller. This is not an unusual scenario."
Eating habits, metabolism affected
Researchers have also noted a link between sleep deprivation in kids and obesity, says Owens. The theory is that a lack of sleep affects metabolic hormones that communicate the sensation of being hungry or full. Sleep-deprived people also eat more high-calorie foods and carbohydrates, she says. Tired children are also less likely to exercise.
There are even some animal models, she says, that indicate a lack of sleep might lower one's immunity to illness.
Sleep-deprived teens get on a treadmill that's hard to get off of, even with catching up on sleep on the weekends.
"They stay up late to finish their homework," says Owens, "but when they're sleep-deprived, you're that much more inefficient in doing any task that requires more sophisticated cognitive functioning, so it takes them longer to finish. So they stay up later and get less sleep. And then that compounds their inefficiency. It's a vicious cycle."
So what's a concerned parent to do? Parents should make sure that their teen's room is a cool, dark and comfortable place. Try to enforce a consistent wake-up time and bedtime. Limit the number of extracurricular activities that crowd a teen's afternoon and push back sleep time. Advise teens to cut out caffeine late in the day. And try to make the 30 minutes before bed a soothing, relaxing time.
"And get the electronics out of the bedroom," advises Mindell.