He used to be my "morning child," the one who'd wake up sunny and raring to go in the morning. But somewhere around middle school he changed. The early-to-bed rules around our house were complied with, reluctantly, but he'd lie awake sometimes for hours, waiting for sleep to come. Weekday mornings became a loud, unpleasant time — for parent and child alike. What happened? Did the pod people do an exchange of children in the night? Come to think of it, he does look different and he certainly now speaks a language I sometimes have difficulty understanding.
The changes, though, seem to have another explanation. In addition to the remarkable physical changes so readily apparent in teens, adolescence brings with it other biological changes that impact on the body's internal "clock," delaying the natural time that teens fall asleep and awaken. Which would be fine if teens ran the world, but their natural inclination runs smack into the fact that many high schools in the United States start before 7:30 a.m.
In addition, they are faced with a world of evening stimulation — part-time jobs, homework, computers, televisions and electronic games in their rooms — that all conspire to delay bedtime. To make matters worse, teens require just as much sleep as they did in elementary school. According to Mary Carskadon, Ph.D., professor of psychiatry and human behavior at the Brown University School of Medicine and a leading sleep researcher, teens require on average more than nine hours of sleep each night.
Sleep and School Performance
In a survey of 3,000 high-school students in Rhode Island, Dr. Carskadon and her colleagues found that the teens on average were getting just 7.3 hours of sleep each night. Only 15 percent of them were receiving 8.5 hours of sleep each night, and a whopping 26 percent were sleeping only 6.5 hours or less. While Carskadon hesitates to equate increased sleep with better grades, since so many factors enter into student performance, she and her colleagues noticed that students who had mostly As on report cards received on average an hour more sleep each night and retired an hour earlier than students who had mostly Ds and Fs on their report cards.
"What it looks like in kids who are getting insufficient sleep is that they are waking up when their internal clock tells them they should be sleepiest," Carskadon says. Falling asleep in early classes is not uncommon. As the day progresses and the external signals — light, activity, even caffeine — kick in, the teens become more alert. "They feel like they're in the pits in the morning, then feel better later and they forget how crummy they felt earlier." By nighttime the cycle repeats itself.
What Can Parents Do About Kids' Sleep?
While biology and school-opening times are largely out of parental control, Dr. Carskadon offers some suggestions to parents for encouraging their teens to get adequate sleep:
- Establish a bedtime. "A lot of kids don't actually have a bedtime," says Dr. Carskadon. "It amazes me. So arranging their day with a sleep schedule in mind" is key to establishing sleep habits that will last a lifetime.
- Promote a healthy lifestyle. That includes forgoing caffeine after school and making the bedroom conducive to sleep. Televisions, video games, computers and stereos all stimulate youngsters.
- Help your teen with time-management skills. Many teens have poor judgment about how long tasks will take, and end up staying up very late to complete assignments.
- Consider limiting the number of activities they do. "In our laboratory, we have a 12-hour rule," explains Dr. Carskadon. "We don't allow people to come into work within 12 hours of their last shift. We should think of kids as shift workers." Many of them go to school a full day and have part-time jobs or school activities that tie them up until late at night. By limiting activities within 12 hours of the start of school, they would have time to complete schoolwork and get to bed at a reasonable hour.
- Make the bedroom dark at night and bright in the morning. These light cues help the body's internal clock to recognize night and day. Eyeshades might be worth a try at bedtime if the room cannot be darkened sufficiently. Bright light in the morning (open curtains or bright artificial light) even helps push bedtime to an earlier hour.
- An afternoon nap. A nap of an hour or less right after school can help a teen remain alert over the next six to eight hours. Avoid naps later in the day, which can interfere with bedtime.
- Sleep in on the weekend, but not too late. While teens need to replenish their "sleep debt" on the weekend, children who stay up very late and "sleep in" past noon on the weekend have the greatest problems. Dr. Carskadon advises getting your teen up two hours or so beyond their usual wake-up time, and perhaps take a nap later in the day. Waking in the afternoon simply makes falling asleep at a reasonable hour on Sunday night nearly impossible — and on Monday morning the cycle begins again.
- Try books on tape. Many preschoolers fall asleep to the soothing sounds of a parent reading a bedtime story. Dr. Carskadon suggests that a book on tape played at a barely audible level can help the transition to sleep for teens. Unlike reading, which requires light in the room, books on tape permit the room to be dark, and the quiet voice can function as "white noise" that also helps prevent stray worries from hijacking a teen from sleep.