Sleep Disorders

What are sleep disorders?
Sleep disorders are sleep problems that, if untreated, can affect a person's physical health, daily activities, and mental health. More than the once-in-a-while tossing and turning or waking up early, sleep disorders are medical conditions that can potentially be serious. But, there is treatment for all of these disorders. Talk with your health care provider if you think you may have a sleep disorder.

Common sleep disorders include:

Sleep apnea. People with sleep apnea stop breathing for a very short time many times during the night. Its main symptoms are loud snoring and feeling sleepy during the day. People with this disorder don't get enough restful sleep at night, making it hard for them to function during the day. Sleep apnea can lead to high blood pressure, heart failure, heart attack, and stroke.

Narcolepsy. When a person has narcolepsy, brain messages about when to sleep and when to be awake get mixed up. This can make a person fall asleep when they don't want to, often without any warning like feeling drowsy. If not controlled with medication, this disorder can cause serious problems in a person's personal, social, and work life. It can also limit a person's activities, such as driving a car, work, and exercising. This disorder may run in families.

Restless legs syndrome. A person with this disorder can have unpleasant feelings or sensations in the legs, mostly in the calves or lower legs. In some cases, the arms may also be affected. These feelings are often described as creeping, crawling, tingling, pulling, or painful. This disorder can be hard to diagnose and is sometimes mistaken for nervousness, insomnia, stress, or arthritis. It seems to affect women more often than men.

Insomnia. People with insomnia have trouble falling asleep or staying asleep during the night. They can wake up often during the night and have difficulty getting back to sleep, or they can wake up too early in the morning. Sleep does not feel satisfying when a person has insomnia. A person can feel sleepy, tired, and irritable during the day and have trouble focusing on tasks.

There is an FAQ on this site for each of these sleep disorders that discusses causes, symptoms, and treatment. Click on the "See also" above to be linked to these FAQs.

Why do I need to worry about sleep?

If you are having problems with sleeping, you are not alone. Studies show that 1 out of every 2 Americans has problems with not being able to sleep at some point in their lives. And, almost 40 million Americans have sleep disorders.

We all know how great we feel when we've had a good night's sleep - we are ready to take on the day and handle whatever may come. But when we've had a bad night's sleep, we also all know the toll it can take on every part of our lives the next day. Sleep can affect not only how we function during the day, but it can also affect our physical and mental health. Not getting enough sleep, even just for one night, can affect our moods and our ability to focus, make decisions, and remember things. When we don't get enough sleep over a period of time, our "sleep debt" adds up and can cause serious problems, such as heart problems, depression, and anxiety. Over time, long-term sleep problems can also affect relationships, work, and quality of life.

What happens when you sleep?

Many people think of sleep as a passive activity, but sleep is actually an active state. It restores us, helps the body to repair damage and grow new cells, keeps the body's nervous system working properly, and helps us to consolidate memory (helps us to remember what we learned during the day). During sleep, a person passes through 5 phases, or stages, of sleep - stages 1, 2, 3, 4 of quiet sleep and stage 5, called REM (rapid eye movement) sleep.

Stage 1 sleep is light sleep, where we drift in and out of sleep and can be woken up easily. Eyes move very slowly and muscle activity slows down.

A person spends almost half of their total sleep time in Stage 2 sleep. Eye movements stop and brain waves (or activity) become slower.

Stages 3 and 4 are called deep sleep. During Stage 3 sleep, brain waves slow down even more and the brain makes mostly delta waves (slow brain waves). The brain makes only delta waves during Stage 4 sleep and there is no eye movement or muscle activity. People often feel groggy and disoriented for a few minutes when they are woken up during deep sleep. Some children have bedwetting, night terrors, or sleepwalking during deep sleep. Deep sleep restores us, helping to grow new cells and repair cells from damage.

A person's breathing becomes more rapid, irregular, and shallow in REM sleep. The eyes jerk quickly in many directions, heart rate increases, and blood pressure rises. When people wake up during REM sleep, they often describe strange dreams that don't make any sense. Most dreaming happens during REM sleep. REM sleep is important, perhaps in part because it stimulates the parts of the brain that help us learn.

A person cycles through these 5 stages of sleep during the night. The first sleep cycles contain short REM periods and long periods of deep sleep. REM sleep periods become longer in length while deep sleep decreases. By morning, almost all sleep time is in stages 1, 2, and REM.

How much sleep does a person need?

There is no hard and fast answer to this question. The amount of sleep a person needs depends on many things, including age. Most adults need at least 7 to 8 hours of sleep per night, although some people may need as many as 10 hours. Children and adolescents need about 9 hours of sleep, while young infants may need around 16 hours per day. Women in the first 3 months of pregnancy often need a few more hours of sleep than normal, and sleep quality is decreased. When people sleep too little over a period of a few days, they build up a "sleep debt," like being overdrawn at a bank. This debt needs to be repaid sooner or later. A person's body is not able to get used to less sleep than they need. Aging does not seem to change the amount of sleep a person needs, although older people tend to sleep more lightly and for shorter periods of time. About half of the people over 65 have frequent sleeping problems, such as insomnia, and deep sleep stages that are shortened or completely stopped. These changes in sleep may be a normal part of aging, or can be caused by medications or treatments for other health problems.

How can I tell if I have a sleep problem or a sleep disorder?

Because so many people "burn the candle at both ends" and have large sleep debts, sleep problems are common. Side effects from medications or treatments and stress and worry can also cause sleep problems. For women, hormone changes during pregnancy, menopause, and the menstrual cycle can cause sleep problems.

Sleep experts say that if you feel sleepy during the day, even when doing something boring, you haven't had enough sleep. If you usually fall asleep within 5 minutes of lying down, you probably have a severe sleep debt, maybe even a sleep disorder. Very short periods of sleep throughout the day (sometimes you may not even know that you are sleeping) are also another sign of a sleep disorder. To learn about the signs for the most common sleep disorders, read the sleep disorder-related FAQs (sleep apnea, narcolepsy, restless legs syndrome, and insomnia) on this site. Talk with your health care provider if you are having a problem with sleep or think that you may have a sleep disorder.

What can I do to get a good night's sleep?

Good sleep habits can help you get a good night's sleep. Here are some tips:

Try to go to bed at the same time every night and get up at the same time every morning. Try not to take naps during the day because naps may make you less sleepy at night.

Try to avoid caffeine, nicotine, and alcohol late in the day. Caffeine and nicotine are stimulants and can keep you from falling asleep. Alcohol can make you wake up later in the night.

Get regular exercise. Try not to exercise close to bedtime because it may stimulate you and make it hard to fall asleep. Experts suggest not exercising for 3 hours before the time you go to sleep.

Don't eat a big meal late in the day, although a light snack before bedtime may help you sleep.

Make your sleeping place comfortable. Be sure that it is dark, quiet, and not too warm or too cold. If light is a problem, try a sleeping mask. If noise is a problem, try earplugs, a fan, or a "white noise" machine to cover up the sounds.

Create a routine to help you relax and wind down before sleep, such as reading a book or taking a bath. Watching the news just before bed may keep some people awake, especially if the news is upsetting.

Try not to use your bed for anything other than sleeping and sex.

If you can't fall asleep and don't feel sleepy, get up and do something else until you feel sleepy. Just make sure that you don't do anything stimulating.

If you have trouble lying awake worrying about things, try making a to-do list before you go to bed. This may help you to "let go" of those worries overnight.

See your health care provider if you think you have a sleep problem or a sleep disorder.

For more information...
You can find out more about sleep disorders by contacting the National Women's Health Information Center at (800) 994-9662 or the following organizations:

National Center on Sleep Disorders Research
Phone Number(s): (301) 435-0199
Internet Address: http://www.nhlbi.nih.gov/sleep

National Heart, Lung, and Blood Institute
Phone Number(s): (301) 592-8573
Internet Address: http://www.nhlbi.nih.gov

National Institute of Neurological Disorders and Stroke
Phone Number(s): (800) 352-9424
Internet Address: http://www.ninds.nih.gov

American Academy of Sleep Medicine
Phone Number(s): 708-492-0930
Internet Address: http://www.aasmnet.org

National Sleep Foundation
Phone Number(s): (202) 347-3471
Internet Address: http://www.sleepfoundation.org

This FAQ has been reviewed by Carl E. Hunt, M.D. of the National Center on Sleep Disorders Research, National Heart, Lung, and Blood Institute, National Institutes of Health.
August 2002