Dr. Greene, my son is 13 years old and I am wondering how much sleep he needs?
Parents are often concerned about the sleep habits of their adolescent children. In my office, I commonly hear either “He sleeps past noon!” or “She’s up all night!” (or both). Naturally, we want our children to be motivated and healthy. If it seems that they are sleeping their lives away, or that they are burning the candle at both ends, our parental instincts rise up.
The ideal amount of sleep at any given age varies widely between individuals, but adolescence is a particularly difficult age at which to pinpoint and ensure the proper amount of sleep.
Observations made in sleep laboratories (Carskadan, et al: Pubertal changes in daytime sleepiness. Sleep 2:453, 460, 1980) suggest that adolescents require more sleep than preteens. On the other hand, observations made in real life (Carskadan: Patterns of sleep and sleepiness in adolescents. Pediatrics 17:5, 1990) suggest that adolescents actually obtain much less sleep than they did during the preteen years.
A study in the Journal of Adolescent Health suggests that 5% of adolescents meet criteria for chronic insomnia, and that sleep deprivation has negative effects on their physical & psychological health, interpersonal interactions, and ability to perform daily activities (Roberts et al: Chronic insomnia and its negative consequences for health and functioning of adolescents: a 12-month prospective study. J Adolesc Health, 2008).
This raises three important questions: First, is this data true? In other words, if researchers in a lab say one thing, and real life says another, are most teenagers really getting insufficient sleep? Second, if most teens do not get enough, why? Are teens just shortsighted, stubborn and out of control? Third, what can be done to help teens get the sleep they need?
The contrast between ideal and actual sleep in teenagers is based on solid research. Its truth is bolstered by the additional observation that excessive sleepiness is a very common complaint among adolescents. Daytime sleepiness is the most common sleep-related disorder of adolescence.
For many years it was felt that the sleepiness of adolescents was their own fault. Their busy social agenda and burgeoning independence led to too many late nights. Recently, however, a different picture has emerged. Independent investigators in Brazil, Japan, and the United States (Andrade, et al; Ishihara, et al; and Carskadon, et al.) have suggested that the internal, biologic sleep-timing mechanism is reset along with the other changes of puberty. Their bodies signal them to go to sleep at a later hour and also to wake later in the morning. They are often incapable of falling asleep earlier. Their school schedules, however, continue to force them out of bed at an early hour. This leads to a population of chronically sleep-deprived adolescents.
Many teens are able to cope with chronic low-level sleep deprivation, often gaining some catch-up by ‘sleeping in’ on the weekends. Others, however, fall asleep in school, have great difficulty getting out of bed in the morning, and/or experience great fatigue, emotional lability, irritability, poor impulse control, and poor decision making.
The average thirteen-year-old needs about 10 hours of sleep in a 24 hour period. However, adequacy of sleep should be determined by a careful evaluation of symptoms rather than by relying on numbers obtained from a large sample of adolescents.
If insufficient sleep is identified, telling the adolescent to “just go to bed earlier” is ineffective and alienating. Either the adolescent’s schedule should be adjusted to complement his body’s internal clock, or the internal clock can be gradually reset through a process called chronotherapy. This will only work if your child understands the problem and is a willing partner in the process.
Sudden changes in sleep schedule do not help to reset the body’s circadian rhythm. Instead, begin by stabilizing bedtime at an hour when it is easy and natural to fall asleep. Then, make the bedtime earlier by about 15 minutes each day (any more than this is too long to lure the circadian rhythm to follow). During this process, naps must be avoided, and the procedure must be followed 7 nights a week. Upon awakening, exercise and exposure to bright light help to fix the new rhythm. (For children whose original bedtime is very late, it can be faster to move the bedtime later by 2 or 3 hours per night around the clock, rather than backward by 15 minutes, — the circadian rhythm will follow. This works extremely well, but requires a committed adult to help enforce waking at the proper time).
Once a new schedule appropriate to the individual is attained, bedtime and wake-up time should be rigidly maintained for 2 to 3 weeks. Later, occasionally staying up late on weekend nights will not reset the clock, as long as he doesn’t sleep in more than 1 or 2 hours later than he would for school.
Some experts recommend giving melatonin about 90 minutes before the desired bedtime as a way to reset the biologic clock. Melatonin is available in health food stores, and now in some drug stores, too. Preliminary studies in adults look exciting, but I’m still cautious about its use in children. While there have been some studies in children suggesting that melatonin may help to reset the body’s sleep-wake cycle, more research is needed (J Sleep Res. 2005 Jun 14(2): 195-7). Melatonin is a potent chemical which also affects the reproductive system. No one really knows what effects it might have on the reproductive system if given before or during puberty.
Many significant events in our recent history are at least partially attributable to sleep deprivation: The crash of the Exxon Valdez, the Union Carbide disaster in Bhopal, the explosion of the space shuttle Challenger (on the part of those responsible for the O-ring), and the nuclear disaster at Chernobyl. More automobile accidents are attributable to sleepiness than to any other single cause. Sleepiness robs more person-years through trauma than does any disease. While most teens handle chronic low-grade sleepiness well, I believe that starting high school an hour or two later would markedly improve the health and behavior of adolescents.