An adolescent's internal clock
Everyone has an internal clock that influences body temperature, sleep cycles and hormonal changes. The biological and psychological processes that follow the cycle of this 24-hour internal clock are called circadian rhythms.
In most people, the various circadian rhythms work together. For example, body temperature starts to rise during the last few hours of sleep — making it easier to wake up in the morning. Most people experience a small drop in temperature between 2 and 4 p.m., which may explain why early afternoon is a popular time for a nap. We then get a second wind around 5 or 6 p.m., which makes it hard to fall asleep around that time.
Before adolescence, these circadian rhythms direct most children to naturally fall asleep around 8 or 9 p.m. Puberty changes an adolescent's internal clock — delaying the time he or she starts feeling sleepy by about two hours. Staying up late to study or socialize with friends can disrupt an adolescent's internal clock even more.
Too little sleep
Adolescents need about nine hours of sleep a night in order to maintain optimal daytime alertness. But only 15 percent actually get that amount of sleep regularly. In a recent survey, more than a quarter of the teens who were interviewed said they usually sleep six hours, or even less, on school nights.
Part-time jobs, homework, school activities and friends often are prioritized higher than is sleep. But sleep deprivation can have serious consequences.
In addition to causing irritability and moodiness, daytime sleepiness makes it more difficult to concentrate and learn. Some exhausted teens sleep through classes, and their grades take a nose dive. Even worse, sleepy drivers — many of them young — can cause deadly auto accidents.
Trying to catch up on sleep during weekends doesn't help much. In fact, it can confuse a teenager's internal clock even more. In these situations, going to bed early won't help matters. Your son or daughter will just lie in bed awake, finally dozing off in the wee hours of the morning.
Many adolescents turn to stimulants such as caffeine and nicotine in an attempt to overcome their daytime sleepiness. Leaving the other dangers of nicotine aside, dependence on its stimulant effects, as well as those of caffeine, can backfire and make it even more difficult to go to sleep at a reasonable hour.
Resetting the clock
Your teen's internal circadian clock can be reset in most cases, but it takes a little effort. Exposure to light seems to play the greatest role in regulating everyone's 24-hour cycles. In fact, many blind people have trouble with their circadian rhythms because they can't see the difference between day and night.
Exposing your child to bright light in the mornings will help his or her body realize that it is time to wake up. A device called a light box can provide enough light to enhance early morning alertness. At the opposite extreme, being in subdued light or darkness at bedtime signals the body that it's time to sleep.
Another method of readjusting a malfunctioning biological clock is called chronotherapy. In a teenager, this most often involves delaying bedtime by two or three hours every night for a progression of nights. For example, if your teen regularly goes to bed at 3 a.m., the first night he or she would stay up until 6 a.m. The next night, he or she would stay up until 9 a.m. This continues until a socially acceptable bedtime is reached.
Products containing melatonin, a sleep-inducing hormone, help some people reset their circadian clocks. Taking the product about five hours before bedtime usually produces the best results. While these supplements can be purchased without a prescription, they should be taken under the supervision of a doctor.
Is it something else?
In some cases, excessive daytime sleepiness can be a sign of something more than a problem with your teen's internal clock. Other problems can include:
- Sleep apnea. When throat muscles fall slack during sleep, they stop air from moving freely through the nose and windpipe, causing labored breathing. In adults, sleep apnea most commonly occurs in obese individuals. Added factors for children are the presence of enlarged tonsils and adenoids, craniofacial abnormalities and neuromuscular disorders. Children with sleep apnea may also exhibit mood swings, inattentiveness and hyperactivity.
- Restless legs syndrome. This condition causes a "creepy" or "crawling" sensation in the legs immediately before bedtime. There is an urge to move the legs, which momentarily lessens the discomfort. Up to 45 percent of the adults with this disorder began experiencing it before age 20. This problem has been associated with iron deficiencies in children.
- Narcolepsy. Sudden daytime sleep, usually for only 15 minutes at a time, can be a sign of narcolepsy. Narcoleptic episodes occur most often after meals, but can occur at any time — even in the middle of conversations.
- Depression. Sleeping too much or too little is a common sign of depression.
Steps to take
Fortunately, most teens just need a little help adjusting their schedules and managing their time to get the right amount of sleep. You might need to prioritize extracurricular activities and consider establishing an official quiet time before bedtime, when loud music, video games and Internet use are restricted or not allowed.
If daytime sleepiness, fatigue or nighttime insomnia persists despite changes that should promote better sleep, contact your child's physician and ask about a sleep evaluation. Your adolescent may have a sleep disorder.