Most teens don't get enough sleep, usually because their schedules are overloaded or they spend too much time texting or chatting on the computer with friends until the wee hours of the morning. Other teens try to go to sleep early, but sleep problems prevent them from doing so.

Over time, nights of missed sleep (whether they're caused by a sleep disorder or simply not scheduling enough time for the necessary ZZZs) can build into a sleep deficit. Teens with a sleep deficit are unable to concentrate, study, and work effectively. They can also experience emotional problems, like depression.

What Happens During Sleep?

As we sleep, our brains pass through five stages of sleep. Together, stages 1, 2, 3, 4, and REM (rapid eye movement) sleep make up a sleep cycle. One complete sleep cycle lasts about 90 to 100 minutes. So during an average night's sleep, a person will experience about four or five cycles of sleep.

Stages 1 and 2 are periods of light sleep from which a person can easily be awakened. During these stages, eye movements slow down and eventually stop, heart and breathing rates slow down, and body temperature decreases. Stages 3 and 4 are deep sleep stages. It's more difficult to awaken someone during these stages, and when awakened, a person will often feel groggy and disoriented for a few minutes. Stages 3 and 4 are the most refreshing of the sleep stages — it is this type of sleep that we crave when we are very tired.

The final stage of the sleep cycle is known as REM sleep because of the rapid eye movements that occur during this stage. During REM sleep, other physical changes take place — breathing becomes rapid, the heart beats faster, and the limb muscles don't move. This is the stage of sleep when a person has the most vivid dreams.

What Prevents an Early Bedtime?

Research shows that teens need 8½ to 9½ hours of sleep a night. So, a teen who wakes up for school at 6 a.m. would have to go to bed at 9 p.m. to reach the 9-hour mark. Studies have found that many teens have trouble falling asleep that early, though. It's not because they don't want to sleep. It's because their brains naturally work on later schedules and aren't ready for bed.

During adolescence, the body's circadian rhythm (an internal biological clock) is reset, telling a teen to fall asleep later at night and wake up later in the morning. This change in the circadian rhythm seems to be due to the fact that the brain hormone melatonin is produced later at night in teens than it is for kids and adults, making it harder for teens to fall asleep.

Sometimes this delay in the sleep-wake cycle is so severe that it affects a person's daily functioning. In those cases it's called delayed sleep phase syndrome.

Changes in the body clock aren't the only reason teens lose sleep, though. Read on to learn about some of the biggest causes of sleep deprivation.

Insomnia

Lots of us have insomnia (trouble falling or staying asleep). The most common cause of insomnia is stress. But all sorts of things can lead to insomnia, including physical discomfort (the stuffy nose of a cold or the pain of a headache, for example), emotional troubles (like family problems or relationship difficulties), and even an uncomfortable sleeping environment (a room that's too hot, cold, or noisy).

It's common for teenagers to have insomnia from time to time. But if insomnia lasts for a month or longer with no relief, doctors consider it chronic. Chronic insomnia can be caused by a number of different problems, including medical conditions, mental-health problems, medication side effects, or substance abuse. Teens with chronic insomnia can often get help for their condition from a doctor, therapist, or other counselor.

For some, insomnia can be made worse by worrying about the insomnia itself. A brief period of insomnia can build into something longer lasting when someone becomes anxious about not sleeping or worried about feeling tired the next day. Doctors call this psychophysiologic insomnia.

Periodic Limb Movement Disorder and Restless Legs Syndrome

Teens with these conditions find their sleep is disrupted by leg (or, less frequently, arm) movements, leaving them tired or irritable from lack of sleep.

In the case of periodic limb movement disorder (PLMD), these movements are involuntary twitches or jerks: They're called involuntary because the person isn't consciously controlling them and is often unaware of the movement.

Teens with restless legs syndrome (RLS) actually feel physical sensations in their limbs, such as tingling, itching, cramping, or burning. The only way they can relieve these feelings is by moving their legs or arms to get rid of the discomfort.

Doctors can treat PLMD and RLS with medications. For some teens, treating an iron deficiency can make the conditions go away.

Obstructive Sleep Apnea

This sleep disorder causes a person to stop breathing temporarily during sleep. One common cause of obstructive sleep apnea is enlarged tonsils or adenoids (tissues located in the passage that connects the nose and throat). Being overweight or obese also can lead someone to develop obstructive sleep apnea.

Teens with obstructive sleep apnea might snore, have difficulty breathing, and even sweat heavily during sleep. Because it disrupts sleep, someone with sleep apnea may feel extremely sleepy or irritable during the day.

Treatment is available for teens with sleep apnea. Those who show signs of the condition, such as loud snoring or excessive daytime sleepiness, should be evaluated by a doctor.

Reflux

Gastroesophageal reflux disease (GERD) is another common culprit of sleep loss. With GERD, stomach acids move backward up into the esophagus, producing the uncomfortable, burning sensation known as heartburn.

GERD symptoms can be worse when a person is lying down. Even if someone doesn't notice the feelings of heartburn during sleep, the discomfort it causes can still interfere with the sleep cycle. Some people find they are better able to sleep by lying in an elevated position or by taking medications.

If your teen suffers from GERD, it could be interfering with his or her sleep. Talk to a doctor about treatment options or lifestyle changes, such as changes in diet.

Nightmares

Most teens have nightmares on occasion. But frequent nightmares can disrupt sleep patterns by waking someone during the night.

Some things can trigger more frequent nightmares, including certain medications, drugs, or alcohol. Ironically, sleep deprivation also can be a cause. The most common triggers for more frequent nightmares are emotional, such as stress or anxiety.

If nightmares are interfering with your teen's sleep, consider consulting a doctor, therapist, or other counselor.

Narcolepsy

Teens with narcolepsy are often very sleepy during the day and have sleep "attacks" that may make them suddenly fall asleep, lose muscle control, or see vivid dreamlike images while dozing off or waking up. Nighttime sleep may be disrupted, with frequent awakenings throughout the night.

Narcolepsy can be disturbing because teens fall asleep without warning, making it hazardous to do things like ride a bike or drive. A teens's schooling, work, or social life can be affected by the unusual sleep patterns.

Narcolepsy is not commonly diagnosed in teens, although many cases go unrecognized. People usually begin to have symptoms between the ages of 10 and 25, but might not be properly diagnosed until 10-15 years later. Doctors usually treat narcolepsy with medications and lifestyle changes.

Sleepwalking

It's rare for teens to walk in their sleep; most sleepwalkers are children. Sleepwalking may run in families. It tends to happen most often when a person is sick, has a fever, is not getting enough sleep, or is feeling stress.

Because most sleepwalkers don't sleepwalk often, it's not usually a serious problem. Sleepwalkers tend to go back to bed on their own and don't usually remember sleepwalking. (Sleepwalking often happens during the deeper sleep that takes place during stages 3 and 4 of the sleep cycle.)

Sometimes, though, a sleepwalker will need help moving around obstacles and getting back to bed. It's also true that waking sleepwalkers can startle them (but it isn't harmful), so try to guide a sleepwalker back to bed gently.

How to Help

If your teen seems to be getting enough rest at night but is still feeling tired during the day, it's a good idea to visit the doctor. Excessive tiredness can be caused by all sorts of health problems, not just difficulties with sleep.

If a sleep problem is suspected, the doctor will evaluate your teen's overall health and sleep habits. In addition to doing a physical examination, the doctor will take a medical history by asking about any concerns and symptoms your teen has, and about his or her past health, your family's health, and any medications your teen is taking. The doctor may also do tests to find out whether any conditions — such as obstructive sleep apnea — might be interfering with sleep.

Different sleep problems are treated differently. Some can be treated with medications, whereas others can be helped by special techniques such as light therapy (where someone sits in front of a lightbox for a certain amount of time each day) or other practices that can help reset a person's body clock.

When teens have sleep problems, doctors often encourage them to make lifestyle changes — like turning off the cell phone or computer before bed, cutting down on caffeine, or avoiding violent video games or movies at night — to promote good sleeping habits.

Reviewed by: Mary L. Gavin, MD
Date reviewed: May 2011