Most teens don't get enough sleep, usually because their schedules are overloaded or they spend too much time texting or chatting with friends until the wee hours of the morning. Other teens try to go to sleep early, but instead of getting much-needed rest, they lie awake for hours. 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 (or sleep debt). Teens with a sleep deficit can't concentrate, study, or work effectively. They also can have 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 wake up easily: 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 harder to wake someone up during these stages, and when awakened, a person often will feel groggy and confused for a few minutes. Stages 3 and 4 are the most refreshing of the sleep stages — this is the type of sleep we crave when we're very tired. They're also the sleep stages during which the body releases hormones that contribute to growth and development. The final stage of the sleep cycle is called REM sleep because of the rapid eye movements that occur: During REM sleep, other physical changes take place — breathing is rapid, the heart beats faster, and the limb muscles don't move. This is the stage of sleep when we have our most vivid dreams. What Prevents an Early Bedtime? Research shows that teens need about 9 hours of sleep a night. So, a teen who needs to wake 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. So, teenagers have a harder time falling asleep. Sometimes this delay in the sleep–wake cycle is so severe that it affects a teen's daily activities. In those cases it's called delayed sleep phase syndrome, also known as "night owl" syndrome. And if your sleep-deprived teen brings mobile devices into bed, surfing or texting late into the night, the light exposure could also disrupt circadian rhythm and make it harder to sleep. 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, bright, 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 call 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. Many teens with chronic insomnia can be helped by a doctor, therapist, or other counselor. For some teens, worrying about the insomnia can make it worse. A brief period of insomnia can build into something longer lasting when a teen becomes anxious about not sleeping or worried about feeling tired the next day. Doctors call this psychophysiologic insomnia. PLMD and RLS Teens with periodic limb movement disorder (PLMD) or restless legs syndrome (RLS) find their sleep is disrupted by leg (or, less commonly, arm) movements, leaving them tired or irritable from lack of sleep. In the case of 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 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. For some teens, treating an iron deficiency can make the problem go away; others might need to take other types of medication. 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 put someone at risk for it. Teens with obstructive sleep apnea might snore, have difficulty breathing, and even sweat heavily during sleep. Because it disrupts sleep, they may feel extremely sleepy or irritable during the day. Treatment can help teens with sleep apnea, so any who have symptoms (such as loud snoring or excessive daytime sleepiness) should be checked by a doctor. Reflux Gastroesophageal reflux disease (GERD) is another common cause 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 elevating their head on a few pillows 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. The most common triggers for more frequent nightmares are emotional, such as stress or anxiety. Other things that can trigger them include certain medicines, and consuming drugs or alcohol. Sleep deprivation (getting too little sleep) also can lead to nightmares. If nightmares are interfering with your teen's sleep, consider having him or her talk to 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 school, work, or social life can be affected by the unusual sleep patterns. Narcolepsy is not commonly diagnosed in teens, but 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 medicines and lifestyle changes. Sleepwalking It's rare for teens to walk in their sleep; most sleepwalkers are kids. Sleepwalking, which may run in families, 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 usually not 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. Treatment for sleep problems can vary. Some can be treated with medicines, while others can be helped with special techniques like 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. Doctors often encourage teens who have sleep problems to make lifestyle changes — like turning off the cellphone or computer before bed, cutting down on caffeine, or avoiding violent video games or movies at night — to promote good sleeping habits./p> Back to Articles Related Articles Sleepwalking Although it can be unnerving to see, sleepwalking is actually very common in kids. Here's how to keep your young sleepwalker safe. Read More How Can I Stop My Nightmares? Find out what the experts have to say. Read More Nightmares Nightmares aren't totally preventable, but parents can help kids feel better when they have one and ease their transition back to sleep. Read More Technology: 5 Ways To Reboot Yourself Sending and receiving messages late at night can disrupt your sleep and leave you tired and unfocused when it's time for school. Read More How Much Sleep Do I Need? Teens need about 8 to 10 hours of sleep each night. But you might not be getting it. Here's why - and tips for getting more shut-eye. Read More All About Sleep Getting enough sleep can be a problem for children of any age. Read this article to learn tips on bedtime schedules and routines for your child. Read More What Should I Do If I Can't Sleep? Find out what the experts have to say. Read More Depression Depression is the most common mental health disorder in the U.S. If you think your child is depressed, you'll want to learn more about what depression is, what causes it, and what you can do to help. Read More 5 Ideas for Better Sleep Insomnia can be a big problem for teens. Read our tips on getting a good night's sleep. Read More Common Sleep Problems Sleep problems can keep some teens awake at night even when they want to sleep. If that sounds like you, find out what you can do. Read More Obstructive Sleep Apnea Brief pauses in breathing during sleep can be normal. But when breathing stops often or for longer periods, it can be a cause for concern. Read More Is it OK to Sleep Less on Weekdays and More on Weekends? Find out what the experts have to say. Read More What to Do if You Can't Sleep Are you having trouble sleeping? Find out how to get your ZZZZZs. Read More What Sleep Is and Why All Kids Need It When you get a good night's sleep, it's like giving your body a tiny vacation. Find out the scoop on sleep in this article for kids. Read More Note: All information is for educational purposes only. For specific medical advice, diagnoses, and treatment, consult your doctor. © 1995-2021 KidsHealth®. All rights reserved. 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