Quiet sleep

Sleep specialists have called non-REM or quiet sleep "an idling brain in a movable body." During this phase, thinking and most physiological activities slow down, but movement can still occur, and a person often shifts position while sinking into progressively deeper stages of sleep.

To an extent, the convention of describing people "descending" or "dropping" into sleep actually parallels changes in brain wave patterns at the onset of non-REM sleep. When you are awake, billions of brain cells receive and analyze sensory information, coordinate behavior, and maintain bodily functions by sending electrical impulses to one another. If you're fully awake, the EEG will record a messy, irregular scribble of activity. Once your eyes are closed and your nerve cells no longer receive visual input, brain waves settle into a steady and rhythmic pattern of about 10 cycles per second. This is the alpha-wave pattern, characteristic of calm, relaxed wakefulness. Unless something disturbs the process, you will soon proceed smoothly through the four stages of quiet sleep.

Dreaming (REM) sleep

Dreaming occurs during REM sleep, which has been described as an "active brain in a paralyzed body." Your brain races, thinking and dreaming, as your eyes dart back and forth rapidly behind closed lids. Your body temperature rises. Unless you have circulatory or other physical problems, the penis or clitoris becomes erect. Your blood pressure increases, and your heart rate and breathing speed up to daytime levels. The sympathetic nervous system, which creates the fight-or-flight response, is twice as active as when you're awake. Despite all this activity, your body hardly moves, except for intermittent twitches; muscles not needed for breathing or eye movement are quiet.

Just as deep sleep restores your body, scientists believe that REM or dreaming sleep restores your mind, perhaps in part by helping clear out irrelevant information. Studies show, for example, that REM sleep facilitates learning and memory. People tested to measure how well they had learned a new task improved their scores after a night's sleep. If roused from REM sleep, however, the improvements were lost. On the other hand, if they were awakened an equal number of times from slow-wave sleep, the improvements in the scores were unaffected. These findings may help explain why students who stay up all night cramming for an examination generally retain less information than classmates who get some sleep.

About three to five times a night, or about every 90 minutes, a sleeper enters REM sleep. The first such episode usually lasts only for a few minutes, but REM time increases progressively over the course of the night. The final period of REM sleep may last a half-hour. Altogether, REM sleep makes up about 25% of total sleep in young adults. If someone who has been deprived of REM sleep is left undisturbed for a night, he or she enters this stage earlier and spends a higher proportion of sleep time in it — a phenomenon called REM rebound.

Sleep architecture

During the night, a normal sleeper moves between different sleep stages in a fairly predictable pattern, alternating between REM and non-REM sleep. When these stages are charted on a diagram, called a hypnogram (see Figure 2), the different levels resemble a drawing of a city skyline. Sleep experts call this pattern sleep architecture.

Figure 2: Sleep architecture Sleep architecture When experts chart sleep stages on a hypnogram, the different levels resemble a drawing of a city skyline. This pattern is known as sleep architecture. The hypnogram above shows a typical night's sleep of a healthy young adult.

In a young adult, normal sleep architecture usually consists of four or five alternating non-REM and REM periods. Most deep sleep occurs in the first half of the night; as the night progresses, periods of REM sleep get longer and alternate with Stage 2 sleep. Later in life, the sleep skyline will change, with less deep sleep, more Stage 1 sleep, and more awakenings.

Circadian rhythm: Understanding your internal clock

Scientists have discovered that certain brain structures and chemicals produce the states of sleeping and waking. Understanding these control mechanisms helps doctors pinpoint what can go wrong and plan effective treatments.

A pacemaker-like mechanism in the brain regulates the circadian rhythm of sleeping and waking. ("Circadian" means "about a day.") This internal clock, which gradually becomes established during the first months of life, controls the daily ups and downs of biological patterns, including body temperature, blood pressure, and the release of hormones.

The circadian rhythm makes people's desire for sleep strongest between midnight and dawn, and to a lesser extent in midafternoon. In one study, researchers instructed a group of people to try to stay awake for 24 hours. Not surprisingly, many slipped into naps despite their best efforts not to. When the investigators plotted the times when the unplanned naps occurred, they found peaks between 2 a.m. and 4 a.m. and between 2 p.m. and 3 p.m.

Most Americans sleep during the night as dictated by their circadian rhythms, although many nap in the afternoon on the weekends. In societies where taking a siesta is the norm, people can respond to their bodies' daily dips in alertness with a one- to two-hour afternoon nap during the workday and a correspondingly shorter sleep at night.

Mechanisms of your "sleep clock"

In the 1970s, the location of the internal clock in rodents was found to be the suprachiasmatic nucleus. This cluster of cells is part of the hypothalamus (see Figure 3), the brain center that regulates appetite and other biological states. When this tiny area was damaged, the sleep/wake rhythm disappeared and the rats no longer slept on a normal schedule. Although the clock is largely self-regulating, its location allows it to respond to several types of external cues to keep it set at 24 hours. Scientists call these cues "zeitgebers," a German word meaning "time givers." These are as follows:

Light. Light striking your eyes is the most influential zeitgeber. When researchers invited volunteers into the laboratory and exposed them to light at intervals that were at odds with the outside world, the participants unconsciously reset their biological clocks to match the new light input. The circadian rhythm disturbances and sleep problems that affect up to 90% of blind people demonstrate the importance of light to sleep/wake patterns.

Figure 3: The sleep/wake control center The sleep/wake control center The pacemaker-like mechanism in your brain that regulates the circadian rhythm of sleeping and waking is thought to be located in the suprachiasmatic nucleus. This cluster of cells is part of the hypothalamus, the brain center that regulates appetite, body temperature, and other biological states.

Time cues. As a person reads clocks, follows work and train schedules, and demands that the body remain alert for certain tasks and social events, there is cognitive pressure to stay on schedule.

Melatonin. Cells in the suprachiasmatic nucleus contain receptors for melatonin, a hormone produced in a predictable daily rhythm by the pineal gland, which is located deep in the brain between the two hemispheres. Levels of melatonin begin climbing after dark and ebb after dawn. The hormone induces drowsiness in some people, and scientists believe its daily light-sensitive cycles help keep the sleep/wake cycle on track.

Childhood

Baby

For an adult to sleep like a baby is not only unrealistic but also undesirable. A newborn may sleep eight times a day, accumulating 18 hours of sleep and spending about half of it in REM sleep. The REM to non-REM cycle is shorter, usually lasting less than an hour.

At about the age of four weeks, a newborn's sleep periods get longer. By six months, infants spend longer and more regular periods in non-REM sleep; most begin sleeping through the night and taking naps in the morning and afternoon. During the preschool years, daytime naps gradually shorten, until by age six most children are awake all day and sleep for about 10 hours a night.

Between age seven and puberty, nocturnal melatonin production is at its lifetime peak, and sleep at this age is deep and restorative. At this age, if a child is sleepy during the day, it's cause for concern.

Adolescence

Adolescent girl

In contrast, adolescents are noted for their daytime drowsiness. Except for infancy, adolescence is the most rapid period of body growth and development. Although teenagers need about an hour more sleep than they did as young children, most of them actually sleep an hour or so less. Parents usually blame teenagers' busy schedule of activities for their grogginess and difficulty awakening in the morning. However, the problem may also be biological. One study indicated that some adolescents might have delayed sleep phase syndrome, where they are not sleepy until well after the usual bedtime and cannot wake at the time required for school, producing conflicts between parents and sleepy teenagers as well as with secondary schools, which usually open earlier than elementary schools. It is unknown whether this phase shift occurs primarily as a physiological event or as a response to abnormal light exposure.

Adulthood

Young man

During young adulthood, sleep patterns usually seem stable but in fact are slowly evolving. Between age 20 and age 30, the amount of deep sleep drops by about half, and nighttime awakenings double. By age 40, Stage 4 sleep has almost disappeared.

Women's reproductive cycles can greatly influence sleep. During the first trimester of pregnancy, many women are sleepy all the time and may log an extra two hours a night if their schedules permit. As pregnancy continues, hormonal and anatomical changes reduce sleep efficiency so that less of a woman's time in bed is actually spent sleeping. As a result, fatigue increases (see "Getting a good night's sleep during pregnancy," below). The postpartum period usually brings dramatic sleepiness and fatigue — because the mother's ability to sleep efficiently has not returned to normal, because she is at the mercy of her newborn's rapidly cycling shifts between sleeping and waking, and because breast-feeding promotes sleepiness. Researchers are beginning to probe whether sleep disturbances during pregnancy may contribute to postpartum depression and compromise the general physical and mental well-being of new mothers.

Women who aren't pregnant may experience monthly shifts in sleep habits. During the second phase of the menstrual cycle, between ovulation and the next menses, some women fall asleep and enter REM sleep more quickly than usual. A few experience extreme sleepiness. Investigators are probing the relationship between such sleep alterations, cyclic changes in body temperature, and levels of the hormone progesterone to see whether these physiologic patterns also correlate with premenstrual mood changes.

Getting a good night's sleep during pregnancy Pregnant woman According to a National Sleep Foundation poll, nearly 8 in 10 women reported more disturbed sleep during pregnancy. Here are some tips to help you get a better night's sleep when you're expecting: Avoid spicy, fried, or acidic foods (such as tomato products), which contribute to heartburn. If you have heartburn, elevate your pillow or raise the head of your bed by placing blocks under the bedposts. Prevent nausea by eating frequent snacks during the day. If you feel drowsy, take a midday nap. Exercise regularly, which will help reduce leg cramps and improve sleep. Cut down on fluids before bedtime to reduce nighttime trips to the bathroom. Use pillows or special pregnancy cushions to support your abdomen.

Middle age

Middle-aged man

When men and women enter middle age, Stage 3 sleep begins to diminish. Nighttime awakenings become more frequent and last longer. It's particularly common for people to wake up after about three hours of sleep. During menopause, many women experience hot flashes that can interrupt sleep, sometimes leading to chronic insomnia. Obese people are more prone to nocturnal breathing problems, which often start during middle age. Here's where it pays to be physically active. Men and women who are physically fit sleep more soundly as they grow older, compared with their sedentary peers.

The later years

Elderly woman

Like younger people, older adults still spend about 20% of sleep time in REM sleep, but other than that, they sleep differently. Deep sleep accounts for less than 5% of sleep time, and in some people it is completely absent. Falling asleep takes longer, and the shallow quality of sleep results in dozens of awakenings during the night. Over a 24-hour period, however, older adults manage to accumulate the same amount of total sleep as younger people, thanks to napping. Doctors used to reassure older people that they needed less sleep than younger ones to function well, but sleep experts now know that isn't true: It was a mistake scientists made when they failed to account for daytime naps logged by older folks. Generally, most sleep experts discourage napping (see "Use strategic naps," below), but if you find that you need a nap, it's best to take one midday nap, rather than several brief ones scattered throughout the day and evening.

Sleep disturbances in elderly people, particularly in those who have Alzheimer's disease or other forms of dementia, are very disruptive for caregivers. In one study, 70% of caregivers cited these problems as the decisive factor in seeking nursing home placement for a loved one. When caregivers of participants in adult day programs were interviewed, more than a third reported being distressed and sleep-deprived because they were looking after someone with disruptive nocturnal behaviors — such as insomnia, nightmares, wandering, physical aggression, loud screaming and talking, or calling for help. In a five-year test project in New York, adult day program participants are being treated for sleep disorders to see if therapy can increase the amount of time that they are able to remain at home.

Although sleep patterns inevitably change with age, older people need not lose alertness and pleasure in life because they can't sleep. No matter how old you are, treatment of sleep disorders and do-it-yourself techniques to maximize sleep quality can bring improvement.

Cut down on caffeine

Caffeine drinkers may find it difficult to fall asleep. Once they drift off, their sleep is shorter and lighter. For some people, a single cup of coffee in the morning means a sleepless night. That's because caffeine is an adenosine blocker, impeding the very neurotransmitter that promotes sleep. Caffeine can also interrupt sleep by increasing the need to urinate during the night.

People who suffer from insomnia should avoid caffeine as much as possible, since its effects can endure for many hours. Because caffeine withdrawal can cause headache, irritability, and extreme fatigue, some people find it easier to cut back gradually than to go cold turkey. Those who can't or don't want to give up caffeine should avoid it after 2 p.m., or noon if they are especially caffeine-sensitive.

Stop smoking or chewing tobacco

Nicotine is a central nervous system stimulant that can cause insomnia. This potent drug makes it harder to fall asleep because it speeds your heart rate, raises blood pressure, and stimulates fast brain wave activity that indicates wakefulness. In people addicted to nicotine, a few hours without it is enough to induce withdrawal symptoms; the craving can even wake a smoker at night. People who kick the habit fall asleep more quickly and wake less often during the night. Sleep disturbance and daytime fatigue may occur during the initial withdrawal from nicotine, but even during this period, many former users report improvements in sleep. Quitting also offers many other health benefits, including a lower risk for cancer, heart disease, and stroke. But those who continue to use tobacco should avoid smoking or chewing it for at least one to two hours before bedtime.

Use alcohol cautiously

Alcohol depresses the nervous system, so a nightcap can help some people fall asleep. However, the quality of this sleep is abnormal. Alcohol suppresses REM sleep, and when it's metabolized a few hours later, the soporific effects are gone. Drinkers have frequent awakenings and sometimes frightening dreams. Alcohol is blamed for 10% of chronic insomnia cases.

Some people fail to get even the short-term benefit from a nightcap because alcohol raises their epinephrine levels and makes falling asleep difficult. Also, because alcohol relaxes throat muscles and interferes with brain control mechanisms, it can worsen snoring and other nocturnal breathing problems, sometimes to a dangerous extent.

Besides contributing to middle-of-the-night wakefulness, alcohol can cause dangerous drowsiness during the day or evening. Drinking during one of the body's intrinsic sleepy times — midafternoon or at night — will induce more sleepiness than imbibing at other times of day. Even one drink can make a sleep-deprived person drowsy. In an automobile, the combined effect of alcohol and sleepiness can be deadly, with the two factors significantly increasing a person's chances of having an accident.

Avoid a sedentary life

Aerobic exercise like walking, running, or swimming promotes restfulness by decreasing the time it takes to fall asleep, reducing the frequency of awakenings, and increasing the amount of deep sleep. According to a Duke University study, physically fit older men fell asleep in less than half the time it took for sedentary men, and they woke up less often during the night.

Exercise is the only known way for healthy adults to boost the amount of deep sleep they get. Researchers from the University of Washington found that older men and women who reported sleeping normally could still increase the amount of time they spent in deep sleep if they engaged in aerobic activity. Exercising five or six hours before bedtime will encourage drowsiness when it's time to go to sleep, but strenuous activity within two hours of bedtime can keep you awake. If you can't exercise several hours before bedtime, exercising earlier in the day can also help you sleep better.

Improve your sleep surroundings

Like Pavlov's dogs, humans learn to respond to environmental cues. Removing the television, telephone, and office equipment from the bedroom is a good way to reinforce that this room is meant for sleeping.

An ideal environment is quiet, dark, and relatively cool, with a comfortable bed and a minimal amount of clutter from daytime responsibilities. Reminders or discussions of stressful issues should be banished to another room.

Ways to control bedroom noise A quiet bedroom can help contribute to a good night's sleep, particularly among older adults, who spend less time in deep sleep and, therefore, are more easily awakened by noises. Here are some ways to reduce or disguise noises that can interfere with sleep: Use earplugs. Decorate with heavy curtains and rugs, which absorb sounds. Install double-paned windows. Use a fan or other appliance that produces a steady "white noise." White noise devices, designed specifically to provide this kind of steady hum, are available in stores. Listen to soothing audiotapes.

Maintain a regular schedule

A regular sleep schedule keeps the circadian sleep/ wake cycle (see "Circadian rhythm: Understanding your internal clock") synchronized. People with the most regular sleep habits report the fewest problems with insomnia and the least feelings of depression. Experts advise getting up at about the same time every day, even after a late-night party or fitful sleep. Napping during the day can also make it harder to get to sleep at night.

Keep a sleep diary

Keeping a sleep diary may help you uncover some clues about what's disturbing your sleep. If possible, you should do this for a month, but even a week's worth of entries can be beneficial.

Use strategic naps

If your goal is to sleep longer at night, napping is a bad idea. Because your daily sleep requirement remains constant, naps take away from evening sleep.

But if your goal is to improve your alertness during the day, a scheduled nap may be just the thing. If an insomniac is anxious about getting enough sleep, then a scheduled nap may improve the quality of nighttime sleep by reducing anxiety (although it'll reduce the time spent asleep at night).

If possible, napping should take place shortly after lunch. People who snooze later in the afternoon fall into a deeper sleep, which causes greater disruption at night. An ideal nap lasts no longer than an hour, and even a 15- to 20-minute nap has significant alertness benefits. Naps that produce lingering grogginess should be shortened or eliminated.

Tips for a better night's sleep Hygiene is the application of scientific knowledge to maintain good health. These procedures are known as "sleep hygiene," because they represent scientific thinking about maintaining healthy sleep patterns. If you suffer from insomnia, try the following to help you get a better night's sleep: Go to bed and wake up at the same time every day, even on weekends. Use the bed only for sleeping, sex, or a very relaxing activity such as reading. Forgo naps, especially close to bedtime. Limit the time you spend in bed. Turn in only when you're sleepy. If you don't fall asleep within 15 minutes or if you wake up and can't fall back to sleep within that amount of time, get out of bed and do something relaxing until you feel sleepy again. Avoid caffeine-containing beverages (coffee, many teas, chocolate, and cola drinks) after 2 p.m., or noon if you're caffeine-sensitive. Avoid eating foods that contribute to heartburn. Don't drink alcohol for at least two hours before bedtime. Limit fluids before bedtime to minimize nighttime trips to the bathroom. Stop smoking, or at least do not smoke for one to two hours before turning in for the night. Exercise regularly, but not too close to bedtime. An afternoon workout is ideal. Keep the bedroom cool, dark, and as quiet as possible. Replace a worn-out or uncomfortable mattress. Take a hot bath before bedtime. Use relaxation techniques before bedtime.

Types of insomnia

Doctors classify insomnia by its duration: transient if it lasts only a few days, short-term if it continues for a few weeks, and chronic if the problem persists.

The causes of transient or short-term insomnia are usually apparent to the sufferer — the death of or separation from a loved one, nervousness about an upcoming event (such as a wedding, public-speaking engagement, or move), jet lag, or discomfort from an illness or injury. Chronic insomnia may be caused by a number of medications or medical conditions (see "Medical conditions and sleep problems"). In these instances, treating the condition, changing the medication, or both may relieve the insomnia.

One common form of persistent sleeplessness is learned insomnia. After experiencing a few sleepless nights, some people learn to associate the bedroom with being awake. Ways to cope with sleep deprivation — napping, drinking coffee, having a nightcap, or forgoing exercise — only fuel the problem. As insomnia worsens, anxiety regarding the insomnia may also worsen, leading to a vicious cycle in which fears about sleeplessness and its consequences become the primary cause of the insomnia.

In rare cases, insomnia begins in infancy, presumably because of an inborn abnormality of the mechanisms that control sleep. When children develop insomnia, physicians may suspect abuse or other trauma.

The first-line treatment: Behavioral changes

For chronic insomnia, the treatment of choice is to change your lifestyle and habits. A careful evaluation can pave the way to better sleep by pinpointing habits that keep you up at night. A sleep specialist trained in behavioral medicine can help people with learned insomnia replace their bad habits with positive ones.

Sleep restriction

People with insomnia often find that spending less time in bed promotes more restful sleep and helps make the bedroom a welcome sight instead of a torture chamber. As you learn to fall asleep quickly and sleep soundly, the time in bed is slowly extended until you obtain a full night's sleep.

Some sleep experts suggest starting with five or six hours at first, or whatever amount of time you typically sleep at night. Setting a rigid early morning waking time often works best. If the alarm is set for 7 a.m., a five-hour restriction means that no matter how sleepy you are, you must stay awake until 2 a.m. Once you are sleeping well during the allotted five hours, you can add another 15 or 30 minutes, then repeat the process until you're getting a healthy amount of sleep.

Sleep Awaken at the same time every day.

Medications for treating insomnia

A variety of products — including prescription medications and over-the-counter preparations — are available for treating insomnia (see Table 1). But their effectiveness varies, and some may carry unpleasant side effects, so talk to your doctor about which option is best for you.

Antihistamines. Antihistamines are the active ingredients in most over-the-counter sleep aids and in motion-sickness pills. Many different over-the-counter sleep remedies are available, but physicians don't usually encourage their use because they're often ineffective and may cause dizziness, blurred vision, constipation, nausea, and next-day grogginess. (For more on over-the-counter products, see "Nonprescription sleep aids".)

Barbiturates. Drugs in this class have been available for nearly a century and were a common ingredient in sleep medications until benzodiazepines became available in the 1960s. Today, sleep experts prescribe barbiturates only in very rare cases. Because these drugs suppress the activity of the entire central nervous system, barbiturate-induced sleep has a lower level of REM sleep than normal. More importantly, barbiturates are highly addictive, withdrawal can be painful and difficult, and an overdose is often fatal.

Benzodiazepines. These medications are frequently prescribed as sleeping pills. Drugs of this class work by enhancing the activity of the inhibitory neurotransmitter GABA, which calms brain activity. Many different benzodiazepines are available. They differ in how quickly they kick in and how long they remain active in the body. Benzodiazepines taken at night can lead to drowsiness and sedation the next day. If your main problem is getting to sleep, your doctor may prescribe a medication that begins working quickly and is short-acting, such as triazolam (Halcion). If your problem is staying asleep, a drug that lasts longer — such as lorazepam (Ativan), estazolam (ProSom), or temazepam (Restoril) — may be necessary. Some drugs in this class also act as muscle relaxants and may be prescribed for this purpose. Additionally, benzodiazepines are used to treat anxiety, so they tend to be useful for patients with anxiety and insomnia that results from it.

Many people who use benzodiazepines develop tolerance — the need for more and more of the drug to obtain the same effect — and after a few weeks, the drugs no longer promote sleep and instead may contribute to rebound insomnia when the medications are stopped. These medications should be discontinued under a doctor's supervision because withdrawal may also lead to muscle tension, restlessness, irritability, or, in rare cases, convulsions.

Imidazopyridines. The class of drugs called imidazopyridines became available in 1992, when the FDA approved zolpidem (Ambien). This medication begins to work after about 30 minutes and leaves the body within five hours. In 1999, zaleplon (Sonata), a shorter-acting imidazopyridine, was introduced. Imidazopyridines specifically enhance the sleep-inducing activity of the neurotransmitter GABA. Unlike benzodiazepines, they do not cause muscle relaxation. Treatment seems to promote a normal pattern of sleep. The most common side effects include headache, dizziness, nausea, and grogginess.

The newest drug in this class, eszopiclone (Lunesta), has just been approved for use in all types of insomnia. It has been shown to be safe and effective even when used for six months. Additional drugs in this class will be released in the near future.

Antidepressants. When depression interferes with sleep, an antidepressant may improve both sleep and mood. If depression is not the problem, a type of older antidepressant medication known as tricyclics is sometimes used because these drugs reduce the length of time it takes to fall asleep and improve the continuity of sleep. At the low doses used to treat sleep disturbance, tricyclic antidepressants seem to be less habit-forming than benzodiazepines and, therefore, less likely to contribute to rebound insomnia. When the tricyclic drug amitriptyline (Elavil, Endep) is used to treat insomnia in people with rheumatoid arthritis or other painful conditions, improved sleep seems to decrease aches and pains.

Other antidepressants, such as the sedative mirtazapine (Remeron), the serotonin-modulator trazodone (Desyrel), and those in the class known as SSRIs (selective serotonin reuptake inhibitors) may also be helpful in treating insomnia. SSRIs include fluoxetine (Prozac), sertraline (Zoloft), fluvoxamine (Luvox), paroxetine (Paxil), and citalopram (Celexa).

Sedatives. Chloral hydrate is an older sedative that doctors sometimes prescribe before certain diagnostic tests. It is occasionally used to treat insomnia. Side effects include rash, nausea, stomach pain, dizziness, and headache.

Other therapies

Two other therapies — light therapy and melatonin — have been used to treat insomnia with varying degrees of success. As of 2005, neither has been found as effective as changing your habits or taking medications.

Light therapy. Some experts recommend exposure to bright light to reset an insomniac's internal clock. Researchers from Flinders University in Adelaide, South Australia, successfully used bright light therapy to improve the sleep of nine insomniacs prone to waking between 3 a.m. and 5 a.m. After two evenings of exposure to bright light, the participants slept more than an hour longer. A comparison group of insomniacs exposed to dim lighting showed no improvement. However, light therapy is not commonly used to treat insomnia at most sleep centers because other treatments such as behavior modification are usually more effective.

Melatonin. In the mid-1980s, researchers began to investigate whether oral doses of melatonin, a hormone secreted by the pineal gland (see "Mechanisms of your ‘sleep clock'"), might help reset the biological clocks of travelers, shift workers, and people with insomnia. It seems to be most helpful for people with low levels of naturally occurring melatonin. So far, however, there are insufficient data for the FDA to approve this supplement as a treatment for insomnia.

In one small study, researchers in Israel tested melatonin as a sleep aid in 12 men and women, average age 76, who had insomnia. People who took melatonin before going to bed fell asleep faster and slept about 10% longer than those who received a placebo. There were no adverse reactions. Other studies, however, found that melatonin did not have any effect on sleep.

A synthetic form of melatonin is sold in health food stores and pharmacies. In the United States, this product — which is not regulated by the FDA — is considered a nutritional supplement, so there is no guarantee of its purity or efficacy. In Great Britain and Canada, melatonin is now classified as a medicine and is no longer available over the counter. To date, there is no reliable information available about its effects during pregnancy or its interactions with other drugs.

Heartburn

Lying down in bed often worsens heartburn, which is caused by the backup of stomach acid into the esophagus. You may be able to avoid this problem by abstaining from heavy or fatty foods — as well as coffee and alcohol — in the evening. You can also use gravity to your advantage by elevating your upper body with the use of an under-mattress wedge or by placing blocks under the bedposts. There are also some over-the-counter and prescription drugs that suppress stomach acid secretion.

Diabetes

Night sweats, a frequent need to urinate, or symptoms of hypoglycemia often rouse diabetics whose blood sugar levels are not well controlled. If diabetes has damaged nerves in the legs, nighttime movements or pain may also disturb sleep.

Cardiovascular disease

Patients with congestive heart failure may awaken during the night feeling short of breath because when they're lying down, extra body fluid accumulates around their lungs. Using pillows to elevate the upper body may help. These people can also be awakened just as they are falling asleep by a characteristic breathing pattern called Cheyne-Stokes respiration, a series of increasingly deep breaths followed by a brief cessation of breathing. Benzodiazepine sleep medications (see "Medications for treating insomnia") help some people to stay asleep despite this breathing disturbance, but others may need to use supplementary oxygen or a device that increases pressure in the upper airway and chest cavity to help them breathe and sleep more normally (see "Continuous positive airway pressure (CPAP)").

A recent study found that men with congestive heart failure frequently experience obstructive sleep apnea (see "Sleep apnea"), which can disrupt sleep, cause daytime sleepiness, and worsen heart failure. In people with coronary artery disease, the natural fluctuations in circadian rhythms may trigger angina (chest pain), arrhythmia (irregular heartbeat), or even heart attack while asleep.

Musculoskeletal disorders

Arthritis pain can make it hard for people to fall asleep and to resettle when they shift positions. In addition, treatment with corticosteroids frequently causes insomnia. You may find it helpful to take aspirin or a nonsteroidal anti-inflammatory drug (NSAID) just before bedtime to relieve pain and swelling in your joints during the night.

People with fibromyalgia — a condition characterized by painful ligaments and tendons — are likely to wake in the morning still feeling fatigued and as stiff and achy as a person with arthritis. Researchers who analyzed the sleep of fibromyalgia sufferers have found that at least half have abnormal deep sleep in which slow brain waves are mixed with waves usually associated with relaxed wakefulness, a pattern called alpha-delta sleep. In one study conducted by researchers at Boston University School of Medicine, 62 people with fibromyalgia received treatment for six weeks with either the NSAID naproxen, the tricyclic antidepressant amitriptyline, both drugs, or a placebo. Almost half of those who took low doses of amitriptyline reported sleeping and feeling better.

Eating disorders

People who have anorexia, an eating disorder characterized by malnutrition and excessive weight loss, get more Stage 1 sleep and less slow-wave sleep than those who maintain a healthy weight. Some people with bulimia, an eating disorder characterized by compulsive overeating and then purging (usually by inducing vomiting or using laxatives), awaken frequently during the night to eat. (For information on food-related sleep disorders, see "Nocturnal eating disorders.")

Kidney disease

Kidney disease can cause waste products to build up in the blood and can result in insomnia or symptoms of restless legs syndrome (see "Restless legs syndrome"). Although researchers aren't sure why, kidney dialysis or transplant does not always return sleep to normal.

Mental illness

Almost all people with anxiety disorders have trouble falling asleep and staying asleep. In turn, not being able to sleep may become a focus of some sufferers' ongoing fear and tension, causing further sleep loss.

General anxiety. Severe anxiety, formally known as "generalized anxiety disorder," is a mental illness that causes a person to have persistent, nagging feelings of worry, apprehension, or uneasiness. These feelings are either unusually intense or out of proportion to the real troubles and dangers of the person's everyday life. People with the disorder typically experience excessive, persistent worry every day or almost every day for a period of six months or more. Common symptoms include trouble falling asleep, trouble staying asleep, and not feeling rested after sleep.

Phobias and panic attacks. Phobias, which are intense fears related to a specific object or situation, rarely cause sleep problems unless the phobia is itself sleep-related (such as fear of nightmares or of the bedroom). Panic attacks, on the other hand, often strike at night. In fact, the timing of nocturnal attacks helped convince psychiatrists that these episodes are biologically based. Sleep-related panic attacks do not occur during dreaming, but rather in Stage 2 and Stage 3 sleep, which are free of psychological triggers. In many phobias and panic disorders, recognizing and treating the underlying problem — often with an anti-anxiety medication — may solve the sleep disturbance.

Depression. Because waking up too early in the morning is a hallmark of depression, a physician evaluating a person with insomnia will consider depression as a possible cause. Almost 90% of people with serious depression experience early-waking insomnia; some depressed people have difficulty falling asleep or get fitful sleep throughout the whole night. In chronic low-grade depression, insomnia or sleepiness may be the most prominent symptom. Laboratory studies have shown that people who are depressed spend less time in slow-wave sleep and may enter REM sleep more quickly at the beginning of the night.

Bipolar disorder. Disturbed sleep is a prominent feature of bipolar disorder (manic-depressive illness). Sleep loss may exacerbate or induce manic symptoms or temporarily alleviate depression. During a manic episode, an individual may not sleep at all for several days. Such occurrences are often followed by a "crash" during which the person spends most of the next few days in bed.

Schizophrenia. Some people with schizophrenia sleep very little when they enter an acute phase of their illness. Between episodes, their sleep patterns are likely to improve, although many schizophrenics rarely obtain a normal amount of deep sleep.

Other neurological disorders

Certain brain and nerve disorders can contribute to sleeplessness.

Dementia. Alzheimer's disease and other forms of dementia may disrupt sleep regulation and other brain functions. Wandering, disorientation, and agitation during the evening and night, a phenomenon known as "sundowning," can require constant supervision and place great stress on caregivers. In such cases, small doses of antipsychotic medications such as haloperidol (Haldol) and thioridazine (Mellaril) are more helpful than benzodiazepine drugs.

Epilepsy. People with epilepsy are twice as likely as others to suffer from insomnia. Brain wave disturbances that cause seizures can also interfere with sleep, causing deficits in slow-wave or REM sleep. Antiseizure drugs can cause similar changes at first, but tend to correct these sleep disturbances when used for a long time. About one in four people with epilepsy have seizures that occur mainly at night, causing disturbed sleep and daytime sleepiness. Sleep deprivation can also trigger a seizure, a phenomenon noted in college infirmaries during exam periods. Each semester, a few students suffer their first seizures after staying up late to study.

Headaches, strokes, and tumors. Two types of headaches — cluster headaches and migraines — may be related to changes in the size of blood vessels leading to the cortex of the brain. Pain occurs when the walls of the blood vessels dilate. People who are prone to headaches should try to avoid sleep deprivation, as lack of sleep can promote headaches. Researchers theorize that as the body catches up on missed sleep, it spends more time in delta sleep, when vessels are most constricted, making the transition to REM sleep more dramatic and likely to induce a headache. Headaches that awaken people are often migraines. But some migraines can be relieved by sleep.

Sleepiness coupled with dizziness, weakness, headache, or vision problems may signal a serious problem such as a brain tumor or stroke, which requires immediate medical attention.

Parkinson's disease. Almost all people with Parkinson's disease have insomnia and may have substantial daytime sleepiness. Treatment with sleeping pills may be difficult because some drugs can worsen Parkinson's symptoms. Some patients who are treated with levodopa, the mainstay of Parkinson's treatment, develop severe nightmares; others experience disruption of REM sleep. However, the use of levodopa at night is important to maintain the mobility needed to change positions in bed. A bedrail or an overhead bar (known as a trapeze) may make it easier for people with Parkinson's to move about and, therefore, lead to better sleep.

Respiratory problems

Circadian-related changes constrict the airway during the overnight hours, raising the potential for nocturnal asthma attacks that rouse the sleeper abruptly. Breathing difficulties or fear of having an attack may make it more difficult to fall asleep, as can the use of steroids, theophylline, or other stimulant medications. One study found that nearly 75% of people with asthma experienced frequent awakenings every week. People who have emphysema or bronchitis may also find it difficult to go to sleep and stay asleep because of excess sputum production, shortness of breath, and coughing.

Thyroid disease

An overactive thyroid can make it difficult to sleep, and night sweats that disturb sleep are a symptom of thyroid dysfunction. Feeling cold and sleepy is a hallmark of hypothyroidism, underactivity of the thyroid gland. Because thyroid function affects every organ and system in the body, the symptoms can be wide-ranging and sometimes difficult to decipher. Luckily, checking thyroid function requires only a simple blood test, so if you notice a variety of unexplained symptoms, ask your doctor for a thyroid test.

Medications that affect sleep

Often, medication rather than illness is the culprit behind sleep problems. A number of drugs are common sleep robbers, while others may cause unwanted drowsiness. Sometimes your doctor may be able to suggest alternatives that do not disrupt sleep.

Medication Review your medications with your doctor.

Antidepressants. The selective serotonin reuptake inhibitors — such as fluoxetine (Prozac), sertraline (Zoloft), and paroxetine (Paxil) — disrupt sleep or produce daytime fatigue in about 15% of those who take them. These medications are increasingly used to treat some of the symptoms of narcolepsy (see "Narcolepsy"), a condition marked by powerful daytime drowsiness and sleep attacks, and a variety of sleep problems, whether or not the person is depressed.

Anti-arrhythmics. These drugs, used to treat heart rhythm problems, may cause daytime fatigue and sleep difficulties at night. Such medications include procainamide, quinidine, and disopyramide.

Sedating antihistamines. These medications, commonly taken to relieve cold or allergy symptoms, also cause drowsiness in most people. They are also the active ingredients in most over-the-counter sleep aids and motion-sickness pills (see "Antihistamines"). To find out if a medication might cause unwelcome drowsiness, check with a pharmacist. If you are taking a sedating antihistamine and are bothered by drowsiness, your physician may recommend a non-sedating alternative that does not readily enter the brain and affect wakefulness and sleep.

Beta blockers. Beta blockers are used to treat high blood pressure, arrhythmias, and angina. These drugs can promote insomnia, awakenings in the night, and nightmares.

Medications containing caffeine. Caffeine, which is in some over-the-counter painkillers and appetite suppressants, is a nervous system stimulant that can induce insomnia. Caffeine makes people feel alert by blocking the action of adenosine, a substance that promotes drowsiness. Caffeine's effects gradually diminish but nonetheless may linger for six or seven hours.

Medications containing alcohol. Cough medicines often contain alcohol, which can suppress REM sleep.

Clonidine. This medication, which acts on nerve cells that respond to the neurotransmitter norepinephrine, is used to treat hypertension and occasionally to curb nicotine craving in people who are quitting smoking. The drug can cause daytime drowsiness and fatigue; it also may interfere with REM sleep. Some people report no problems with clonidine; others note restlessness, early morning awakening, and nightmares.

Corticosteroids. Corticosteroids such as prednisone, which are used to suppress inflammation and asthma, often cause daytime jitters and nighttime insomnia.

Diuretics. Diuretics, which are taken to rid the body of excess sodium and water, can interfere with sleep by inducing urination throughout the night. Potassium deficiency, a common side effect of some diuretics, can cause painful nocturnal cramping of calf muscles during sleep.

Nicotine patches. Patches used to curb smoking deliver small doses of nicotine into the bloodstream around the clock. People who use them often suffer insomnia or experience disturbing dreams.

Sympathomimetic stimulants. Sympathomimetic stimulants — such as dextroamphetamine (Dexedrine), methamphetamine (Desoxyn), methylphenidate (Ritalin), and pemoline (Cylert) — are powerful central nervous system stimulants that enhance the effect of brain chemicals involved in wakefulness. People taking these agents have difficulty falling asleep; once asleep, they spend less time in REM sleep and non-REM deep sleep. When the drug is discontinued, extreme sleepiness and a craving for REM sleep may follow.

Theophylline. This respiratory stimulant used to treat asthma is chemically related to caffeine. Many people who use it require doses that are high enough to disrupt sleep.

Thyroid hormones. Thyroid hormones taken to counteract the effects of an underactive gland may cause sleeping difficulties at higher doses.

Snoring

With the onset of sleep, muscles in the airway relax and the airway narrows. Snoring occurs when the airway narrows excessively, causing turbulent airflow. This, in turn, causes the surrounding tissue to vibrate, producing noise. More than one-third of adults in one survey said they snored at least a few nights a week in the previous year.

The source of snoring depends on where in the upper airway the narrowing is. When a person's nasal passages are swollen by a cold, allergies, or a reaction to smoking, temporary snoring may occur. For someone with a deviated septum, the problem is ongoing. A particularly large uvula; enlarged tonsils, adenoids, or tongue; an elongated soft palate; or a very small jaw may also contribute to snoring.

In yet other people, the culprit may be poor muscle tone in the tissues around the upper airway. Excess fat in the neck area may reduce the width of the air passage and promote snoring. The hormones progesterone and estrogen may play a protective role; prior to menopause, women snore less than men, but snoring increases among women later in life. Many women snore late in their pregnancies, a phenomenon attributed to hormone-related swelling of airway tissues.

Although snoring is rarely life-threatening, sleep specialists take even simple snoring seriously. A person who snores heavily deserves a thorough examination of the throat, mouth, palate, tongue, and neck and may need to undergo sleep studies.

Sleep apnea

Sleep apnea is a life-threatening condition that affects approximately 18 million adults in the United States, and is most common among overweight men. In sleep apnea, the airway becomes blocked or breathing muscles stop moving. Breathing stops or becomes shallower hundreds of times each night. People with sleep apnea are often less aware of their fatigue and sleepiness than are people with other types of sleep disturbances. Sleep experts say that doctors should be more vigilant in diagnosing apnea because it contributes not only to daytime sleepiness, but also to traffic accidents, cognitive difficulties, and heart problems.

Until recently, sleep apnea was considered uncommon, and it often remained undiagnosed. Physicians rarely checked for it except in the stereotypical patient — an overweight, middle-aged man who snored. But in 1993, researchers at the University of Wisconsin School of Medicine learned that apnea is more common in both men and women than previously thought. They looked for sleep apnea in 602 state employees, ages 30–60, as part of a larger sleep study, and were surprised to find that 9% of women and 24% of men had at least five episodes of reduced breathing, or hypopnea, per hour. About 4% of men and 2% of women were estimated to have the full syndrome of sleep apnea, which includes abnormal breathing events and daytime sleepiness.

Treatments for apnea

Lifestyle changes, medication, air pressure devices, oral appliances, and surgery are used to treat obstructive sleep apnea. Physicians usually advise people with this condition to lose weight and avoid alcohol and sedatives. Sleeping in a different position may help if you experience apnea only when lying on your back. If the appropriate lifestyle changes don't reduce apnea, continuous positive airway pressure (CPAP) or oral appliances may be effective. Selective serotonin reuptake inhibitors (SSRIs) have a mild positive effect on airway muscle tone and are helpful for some people. In some cases, surgery may be necessary. It's best to get a second opinion from a specialist with expertise in sleep disorders before agreeing to surgery.

Therapy for central sleep apnea usually involves treating the underlying medical condition that has disrupted breathing. Sometimes CPAP, oxygen, or medications are helpful (see Table 2).

Table 2: Medications for sleep apnea
Obstructive sleep apnea
Class or generic name	Brand name	Side effects	Comments
SSRI antidepressants*	Prozac, Zoloft, Paxil	Upset stomach, nightmares, dry mouth, decreased sexual function	Minimally effective
Tricyclic antidepressants*	Anafranil, Elavil, Aventyl, Norpramin, Tofranil	Blurred vision, confusion, constipation, decreased sexual function	Minimally effective
modafinil	Provigil	Headache, upset stomach, nervousness	Approved to treat residual daytime sleepiness after treatment with CPAP; does not treat apnea itself.
Central sleep apnea
Class or generic name	Brand name	Side effects	Comments
acetazolamide*	Diamox	Tingling in arms and legs; nausea, vomiting, or diarrhea; changes in hearing; loss of appetite	Not to be used if allergic to sulfa drugs; not to be used in conjunction with high doses of aspirin; should not be used by persons with a history of kidney stones.
theophylline*	Theo-24, Uniphyl	Heartburn, vomiting, rash	Should be used with caution by people with a history of convulsions, heart failure, or liver disease.
oxygen	n/a	Nasal dryness and irritation	Eliminates apnea in some patients.
*Although the FDA has not approved drugs in this class for this sleep apnea, physicians have found that they often help people with this condition and therefore prescribe them.

Continuous positive airway pressure (CPAP). Usually, this is the first treatment recommended for people with sleep apnea. If you have obstructive sleep apnea, CPAP can keep your airway open during breaths, preventing airway collapse and making sleep more restful. It may also help some people with central sleep apnea sleep better. The CPAP devices use a compressor to deliver pressurized air through a mask that fits snugly over your nose or nose and mouth. The machine can be placed on a night stand by the bed. CPAP has become more comfortable in the past few years; newer models are lighter and quieter, and many offer options such as warmed humidified air (which alleviates nasal congestion, skin dryness, and dry mouth) and an internal regulator that eases pressure when you're breathing well on your own.

Sleep apnea The CPAP device keeps the airway open during sleep by providing a pressurized flow of air. Newer models for home use are more comfortable than earlier versions.

People usually try CPAP for the first time in a sleep laboratory. A technician adjusts the pressure while the patient sleeps. Most people find it difficult at first to breathe out against a constant stream of air and to learn to sleep with their mouth closed. However, there is generally a great improvement in the amount of time spent in restorative deep sleep. Many people report a superb night's rest immediately, and tests show their alertness is improved the next day. In many cases, CPAP also reduces or eliminates hypertension. For some people, CPAP may be a lifelong treatment.

Bi-level positive airway pressure (bi-level PAP). For people who have difficulty exhaling against the pressure of CPAP, a refinement called bi-level PAP (often referred to by the trademarked name BiPAP) may be more tolerable. It delivers air under high pressure as the sleeper inhales and switches to lower pressure during exhalation.

Oral appliances. Oral appliances that reposition the lower jaw and tongue, permitting the airway to remain open, can reduce or eliminate sleep apnea. Such devices are available from dentists trained in treating sleep apnea.

Corrective jaw surgery. Surgery to move the upper or lower jaw forward may enlarge the upper airway for some people with obstructive sleep apnea.

Somnoplasty. Along with treating snoring, somnoplasty (see "Somnoplasty") also is sometimes used to treat sleep apnea when other treatments have not helped. It's not yet known what percentage of patients benefit from somnoplasty.

Tracheostomy. Tracheostomy, the first treatment for sleep apnea, is rarely used today. In tracheostomy, the surgeon makes a small hole through the lower neck into the airway below its point of collapse and inserts a tube. During the day, the tube is plugged; at night, it's opened to allow air to enter, bypassing the obstructed area. Tracheostomy is 100% effective, but it is reserved for life-threatening cases or when all other treatments have failed.

Uvulopalatopharyngoplasty (UPPP). In UPPP, a surgeon removes loose or excess tissue from the uvula, the tonsils, and a rim of loose tissue at the edge of the soft palate. Although the operation is often described as a "tightening of loose tissue" or a "revision" of the upper airway, it involves removing anatomical structures. Recovery is similar to that following a tonsillectomy: You usually have a severe sore throat for a couple of weeks. The hospital stay usually lasts two days, and you'll be monitored overnight to assess the effectiveness of the procedure. UPPP helps about half of those who undergo it. The rest may need to have further upper airway surgery or use CPAP.

Restless legs syndrome

An estimated 1%–5% of adults have restless legs syndrome (RLS), a neurological disorder characterized by strange aching, crawling, or painful sensations in the lower legs that can be temporarily relieved by moving the legs.

Sleep deprivation is a major problem for individuals with RLS, as the symptoms are most prominent, or only occur at night. People develop a variety of coping strategies, such as pacing, doing knee bends, rocking, or stretching the leg muscles. Symptoms are worse when sitting still, and the irresistible urge to move can make it difficult for people with RLS to take car or plane trips, enjoy a movie, or even hold a desk job.

Bed This neurological condition makes it hard to stay in bed at night.

At night, RLS symptoms may compel the person to get in and out of bed many times. Sleep disturbance can be profound. In recognition of the restless nights suffered by people with RLS, the nonprofit Restless Legs Syndrome Foundation titled its newsletter NightWalkers (see "Resources").

Because the symptoms sound bizarre or vague, and the need to be constantly mobile seems like nervousness, people with RLS are frequently thought to have psychiatric problems. In the past, they were often misdiagnosed as having hypochondria, manic-depressive illness, or a stress-related disorder. Children who have RLS are often diagnosed as having attention deficit disorder. Some people report that their symptoms started in adolescence and that adults attributed the problem to growing pains or back trouble.

RLS has a genetic basis, with as many as half of people with RLS noting that other members of their family have similar symptoms. Each child of an affected person has a 50% chance of inheriting the condition.

RLS usually worsens with age. Many people don't seek medical attention until their late 30s. Women may find that symptoms flare up during menstruation, pregnancy, or menopause. At least one in four pregnant women experiences restless legs.

The daytime symptoms sometimes abate for a few hours, days, or even years. Some people get temporary relief by rubbing or squeezing their leg muscles, wrapping their legs in bandages, or applying cold or warm compresses.

Restless legs can be a complication of alcoholism, iron deficiency anemia, diabetes, heart failure, or kidney failure. In some people, caffeine, stress, nicotine, fatigue, or prolonged exposure to a cold or very warm environment can worsen the symptoms. Certain medications — including antihistamines, antidepressants, or lithium — can exacerbate RLS.

Periodic limb movement disorder

Periodic limb movement disorder (PLMD), a neurological condition, is similar to RLS, except that it occurs during sleep. During the night, the leg muscles involuntarily contract every 15–45 seconds, which causes jerking movements that at least partially rouse the person from sleep. The same movement (involving the hip, knee, or ankle) may be repeated hundreds of times a night. Unless a bed partner complains, the affected person will likely remain oblivious to the movements and baffled at feeling tired after what he or she believes was a full night's rest.

PLMD is more common than its relative, RLS. Up to 50% of elderly people experience such leg movements during sleep. Nearly everyone with RLS will also have PLMD.

Treatments for movement disorders

There is no single diagnostic test for RLS or PLMD, and standard neurological examinations often reveal no abnormality.

Dopaminergic drugs that ease the tremors of Parkinson's disease also reduce the number of leg movements and thus improve quality of life for people with RLS and PLMD. Levodopa-carbidopa (Sinemet), pergolide (Permax), and pramipexole (Mirapex) are first-line treatments for these disorders (see Table 3). While the drugs used to treat RLS and PLMD are the same as those used in treating Parkinson's disease, people with these sleep disorders are no more likely to develop Parkinson's disease than other individuals.

People with mild movement disorders may be prescribed diazepam (Valium), clonazepam (Klonopin), or temazepam (Restoril), which may help them stay asleep during leg movements. Most people who take these medications for insomnia develop a tolerance to them after a few weeks, but this doesn't seem to happen when such drugs are taken for RLS.

Because of the potential for addiction, most physicians are reluctant to treat sleep disturbances with opiates (opium-derivative drugs) such as propoxyphene (Darvon) and oxycodone (OxyContin). However, these drugs often help people with severe RLS symptoms that resist other treatments. The opiates decrease the discomfort of RLS and, for some patients, dramatically reduce leg movements at night. When properly used, they may provide long-term benefit with little risk of addiction.

Symptoms of narcolepsy

Narcolepsy may manifest itself in any of several ways:

• Excessive sleepiness. People with narcolepsy often feel extremely tired and struggle to stay awake during the daytime.

• Sleep attacks. A person may suddenly fall asleep for 5–10 minutes when relaxing or even while carrying on a conversation. If REM sleep and dreaming occur immediately, the individual sometimes makes conversation that is appropriate to the dream instead of the actual situation.

• Cataplexy. In cataplexy, the brain mechanism that paralyzes muscles during REM sleep becomes activated during the day. Thus, you may be fully alert but suffer partial paralysis or a complete muscle collapse, often brought on by laughter, anger, or other strong emotions. Cataplexy may set in several years after daytime sleepiness first appears, although sometimes it's the first symptom of narcolepsy. In mild cataplexy, your knees may buckle, or the muscles of your jaw or neck may become weak and difficult to control. When it's severe, the muscles become completely paralyzed, and you may fall to the ground. You are usually fully awake and aware of what's going on, but unable to talk. Although a few people then fall asleep, most recover spontaneously after several seconds or minutes.

• Sleep paralysis. A terrifying feeling of paralysis may occur during the transition between wakefulness and sleep if REM begins before a person is fully asleep. Although muscle control usually returns within a few minutes, it can cause great anxiety.

• Hypnagogic hallucinations. When REM dreaming occurs during wakefulness, the vivid and often frightening images, known as hypnagogic hallucinations, are difficult to distinguish from reality. A person may see prowlers or believe that his or her house is on fire. This usually happens just at sleep onset or upon awakening. This condition can be confused with mental illness because its symptoms resemble those of some psychotic disorders.

• Disturbed nighttime sleep. Just as sleep intrudes during the day, unwelcome awakenings can occur at night, depriving narcoleptics of restorative rest and exacerbating daytime drowsiness. Some feel as if they have hardly slept at all.

• Automatic behavior. Because of their profound sleepiness, people with narcolepsy perform many routine tasks without being fully aware of what they are doing. For example, one man washed and dried the dishes and then stacked them in the refrigerator but had no recollection of doing so.

Treatments for narcolepsy

There is currently no cure for narcolepsy. Treatment is geared toward improving wakefulness during the day and preventing REM-related symptoms.

Most people require sympathomimetic stimulant medications such as methylphenidate (Ritalin), pemoline (Cylert), and dextroamphetamine (Dexedrine) to counter sleep attacks and drowsiness (see Table 4). Because these medications have been abused as recreational drugs and misused as diet pills, drug enforcement agencies often require physicians to provide extensive documentation when they prescribe them. Even with medication, however, people are never as alert as they would be if they didn't have this condition.

Modafinil (Provigil), a once-a-day medication to promote wakefulness, received FDA approval for treating daytime sleepiness in 1999. This medication has a different mechanism of action than the older stimulants and doesn't cause euphoria or weight loss or other side effects, so there's less concern about its misuse or abuse. However, it is less potent.

In most people, antidepressants that suppress REM sleep — such as fluoxetine (Prozac), sertraline (Zoloft), paroxetine (Paxil), clomipramine (Anafranil), or venlafaxine (Effexor) — can also prevent cataplexy and other REM-related symptoms.

The newest medication for cataplexy is sodium oxybate (Xyrem), also known as gamma hydroxybutyrate (GHB). This medication is effective in decreasing the number of cataplexy episodes and may improve nighttime sleep as well. Because of its chemical properties, it must be taken at bedtime and again during the middle of the night. Xyrem is tightly regulated because of its potential for misuse; it can cause daytime drowsiness and amnesia and has been associated with criminal acts such as date rape.

Somnambulism and somniloquy

Somnambulism, or sleepwalking, occurs during partial awakening from deep sleep. Sometimes sleepwalkers carry out complex actions; at other times they simply pace or sit on the edge of the bed performing repetitive behaviors. They can be difficult to awaken and typically have no memory of the episode in the morning. There have been reports of somnambulists committing murder, although this is extremely rare. Fortunately, episodes of sleepwalking are usually brief and benign, with few people endangering themselves or others. Scientists used to believe that sleepwalkers were acting out their dreams, but experts have determined that sleepwalking does not occur during dreaming.

Sleepwalking is common in children and probably occurs because their brains have not mastered regulation of sleep and waking. The tendency seems to be inherited. Although people are more likely to sleepwalk when they're anxious or fatigued, there is little correlation between somnambulism and psychological problems. If the condition continues beyond puberty, the individual should be evaluated to determine whether sleepwalking is the result of nighttime epilepsy or a reaction to medication, extreme stress, or another sleep disorder. Cases where the disorder presents a risk of injury may be treated with medications such as benzodiazepines.

Somniloquy, or talking in one's sleep, is nothing to worry about. People are more likely to talk in their sleep during times of stress or illness. Talking can occur during any or all stages of sleep. When awakened, people who talk in their sleep rarely remember what they said. Only occasionally can someone who talks in his or her sleep hear and respond to what someone else says.

Nocturnal eating disorders

Two types of nighttime eating disorders exist. Nocturnal eating syndrome occurs most commonly in people with daytime eating disorders or depression. They are usually light sleepers and awaken frequently. Within minutes after getting out of bed, people with this condition raid the refrigerator and begin wolfing down food. Although they aren't really hungry, they can't go back to sleep without eating. In some people with this type of disorder, overeating occurs only during sleep hours, and not at times when they are fully awake. The person is fully alert during the episode and can recall it the next day. This type should be treated as an eating disorder.

Refrigerator Frequent nocturnal eating may suggest a sleep disorder.

The other disorder, called sleep-related eating disorder, is a combination of a sleep disorder and an eating disorder. People with this disorder experience partial arousals similar to sleepwalking but respond by eating. Often they consume unhealthful, high-calorie food. They report being half-awake or asleep during the episodes and have very poor memory of the events or no recollection at all. This type also occurs more frequently in those with eating disorders and depression. However, treatment should be for both the sleep disorder and the existing eating disorder.

Nocturnal eating occurs in children and adults, and it can sometimes be traced to an illness or traumatic event. A medical evaluation may reveal an ulcer, a history of strict dieting, bulimia, or a sleep problem such as narcolepsy (see "Narcolepsy"), sleepwalking, sleep apnea (see "Sleep apnea"), or periodic limb movements (see "Periodic limb movement disorder"). Sometimes medications prescribed for depression or insomnia can cause this disorder. A number of medicines have been tried to treat these disorders, including dopaminergic agents, anticonvulsants, antidepressants, and opiates, but results have been mixed.

Bedwetting

Bedwetting, known medically as nocturnal enuresis, is common among children. Up to 40% of 4-year-olds and up to 5% of 10-year-olds wet the bed. Bedwetting, which occurs more frequently among boys than girls, is usually due to slow maturation of bladder control. Occasionally, it results from psychological stress. When a specific physical problem such as a structural abnormality of the urinary tract, diabetes, a urinary tract infection, or a nervous system defect leads to bedwetting, the child will also have difficulty with daytime bladder control. Almost all bedwetting children eventually stay dry at night.

It's important for adults to understand that children have little control over bedwetting and that admonishments and punishments won't solve the problem. Instead, doctors often prescribe a retraining program involving the use of an alarm that wakes the child upon the first sign of wetness. Over two to three months, the child will come to recognize the need to urinate and will learn to get up and go to the bathroom.

Bedwetting occurs in a very small percentage of adults and is often due to an underlying medical problem or excessive caffeine or beer consumption. In men, an enlarged prostate gland that presses against the bladder may be to blame. Bedwetting may be a side effect of diuretic pills or a sign of diabetes, a bladder or kidney problem, epilepsy, or serious obstructive sleep apnea (see "Obstructive sleep apnea"). Treatment for adult bedwetting depends on the cause.

REM behavior disorder

Most people make subtle twitching movements during REM, but occasionally sleepers shout, punch, or otherwise act out their dreams. Men over age 50 are more likely to have this condition, known as REM behavior disorder. An estimated 85% of people diagnosed with it have hurt themselves, and nearly half have injured their bed partners.

Approximately one-third of people with REM behavior disorder develop Parkinson's disease within three years of the onset of the disorder, suggesting that similar brain structures are implicated in both conditions.

If the person is at risk for harming himself or others or is having daytime sleepiness from the sleep disruption, a medium-acting benzodiazepine may help suppress symptoms. Until the problem is under control, people can protect themselves and loved ones by sleeping in a separate room and putting sharp or breakable objects out of reach.

Nightmares and sleep terrors

Nightmares and sleep terrors are nocturnal attacks of fear or panic that interrupt sleep in some people. Nightmares, which usually occur early in the morning, are bad dreams that become so threatening that a person wakes in a state of fear and agitation. Nightmares occur mainly during REM sleep when the body barely moves.

Unlike a nightmare, a sleep terror can be quite dramatic to witness. The sleeper may let out a bloodcurdling scream, sit bolt upright, and attempt to fight or flee. During an episode, which may last as long as 15 minutes, a person may seem confused and agitated. After the spell is over, he or she is likely to go right back to sleep and later may not remember what happened.

Sleep terrors occur during non-REM sleep, usually in the first hour or so after going to bed. They appear to run in families and occur most often in children. Adults with sleep terrors tend to be more agitated, anxious, and aggressive than children who have this problem. When the episodes involve violent or injurious behavior, medical treatment may be recommended. Some doctors prescribe medications such as benzodiazepines that suppress deep sleep. Hypnosis or a relaxation technique known as guided imagery may also be helpful.

Sleep-related panic attacks. People with this condition awaken suddenly because of episodes of intense panic characterized by a racing heartbeat, sweating, trembling, breathlessness, or the feeling that they may be dying. Anti-anxiety drugs are often useful for both daytime and nighttime attacks.

Delayed sleep phase syndrome

Almost everyone is programmed for a day that lasts slightly longer than 24 hours, but "night owls" are less sensitive to the environmental cues that help most people maintain a 24-hour cycle. Left to their own devices, they would generally go to sleep and wake up later each successive day. Only by relying on external cues, such as alarm clocks, do they manage to stay in sync. Night owls have trouble getting anything done in the morning.

They may be able to gradually synchronize their schedule with others by going to bed and getting up at the same time every day. However, it's easy for their sleep patterns to go awry when they go on vacation or retire. Night owls often find that a minor shift in sleep/wake cycles such as the onset of daylight savings time, a coast-to-coast trip, or a weekend of late-night parties can throw them off kilter unless they force themselves to get up at the same time.

Resetting your internal clock

If you're already going to bed late and getting up hours later than everyone else, you can reset your biological clock by moving your bedtime progressively later until you've shifted around the clock and are back in sync. To do this, go to bed two hours later each night. Once you have synchronized your schedule to match that of the other people around you, wake yourself up at the same time each day.

Alarm clock You can reset your biological clock.

Often a delayed sleep phase can be reset in a single weekend — something teenagers do routinely. This requires staying up all night on Friday and all day Saturday, then going to bed around 10 p.m. On Sunday, get up at 7 a.m. From then on, adhere closely to the same bedtime and waking time seven days a week.

Exposure to bright light as directed by a sleep specialist — a technique known as light therapy — may be useful in treating delayed sleep phase syndrome. Upon awakening, patients typically sit for 30 minutes facing a specially manufactured box that emits bright light with a minimal amount of ultraviolet light. Melatonin may also have a role; taking 1–6 mg three hours before your current bedtime may help advance your sleep schedule.

Advanced sleep phase syndrome

People whose body rhythms follow a cycle of less than 24 hours go to bed earlier and earlier and eventually can't stay awake past early evening. This condition, called advanced sleep phase syndrome, is more common among older people. Treatments being studied include bright light therapy in the evening, which helps reset the body's clock, and carefully timed doses of melatonin.

Jet lag

People who cross several time zones find that ambient light and other environmental cues may make their internal clocks go haywire. In addition to having headaches, stomach upset, and difficulty concentrating, they may suffer from shallow and fitful sleep.

Younger people usually adapt more quickly to time changes than older ones. It takes about a day to adjust for every time zone crossed. Many people have more difficulty traveling eastward, but older people may have more symptoms traveling westward.

The best way to handle jet lag is to try to sleep only at night and to get up early in the morning, although it may be difficult the first few days. This way your body can start adjusting to the new time zone as soon as possible (see "Ways to avoid jet lag" below). Short-term use of over-the-counter or prescription sleep aids to help you sleep at night also can be helpful.

Sunday insomnia

It's common for people to have trouble falling asleep on Sunday nights. While anxiety about work or school on Monday is a potential cause, often the most important factor is weekend changes in sleep habits. When someone stays up later Friday night and sleeps in Saturday morning, he or she is primed to stay up even later Saturday night and sleep in the next day. By Sunday evening, the body's clock is programmed to stay up late.

People who have developed a pattern of Sunday insomnia may feel their anxiety mount as they anticipate a difficult night ahead. The solution to the Sunday blues is to maintain a weekday rising schedule on the weekends. When self-discipline fails, going to bed early on Sunday only results in frustration. A more effective approach is to do something pleasant until drowsiness sets in and get up when the alarm goes off on Monday morning no matter how little sleep you've gotten.

Shift work

More than 20% of American workers — including health care workers, police officers, security guards, and transit workers — are on the evening or night shift. About 60%–70% of shift workers experience sleep disturbances. These people fall asleep on the job two to five times more often than day-shift workers do. Sleepiness can be catastrophic for people in these vital roles. Sleep-deprived physicians, for example, make a greater number of errors than their better-rested colleagues, and it's common for fatigue to play a role in overnight rail, plane, truck, and maritime accidents.

Shift workers' sleep disorder can be eased somewhat by incorporating scheduled breaks, by rotating shifts from day to evening to night rather than the other way around, or by maintaining the same schedule seven days a week. Shift workers can also benefit from practicing good sleep hygiene (see "Tips for a better night's sleep"). They should reserve the bedroom for sleep and sex, keep their bedroom cool and comfortable, relax before falling asleep, and maintain a regular routine for preparing for bed. Dark curtains or eyeshades can keep daylight out, and running a fan can help block external noise. Shift workers need to enlist the help of family members to get enough sleep while maintaining a schedule at odds with the rest of the world. The most successful shift workers are those who block out time for sleep in advance and then are vigilant about protecting their sleep blocks from outside intrusions. Light therapy is sometimes recommended to help people get used to a new schedule, as is the short-term use of sleep medications.

Seasonal affective disorder (SAD)

In some parts of North America, abbreviated sunlight in the winter means that people don't get as much exposure to sunlight. As the days get shorter, some people find themselves depressed, sleepy, and drawn to high-carbohydrate foods.

Researchers speculate that people who suffer from this condition, called seasonal affective disorder (SAD), produce too much melatonin (or are extra-sensitive to normal amounts of this drowsiness-inducing hormone) and don't make enough serotonin, which may induce the craving for carbohydrates. Exposure to bright light in the morning for 30 minutes may alleviate the symptoms of SAD and help people wake up in the mornings. Antidepressants can also be helpful.

When to seek help

The American Academy of Sleep Medicine recommends seeking medical advice if sleep deprivation has compromised your daytime functioning for more than a month.

You shouldn't hesitate to ask for help when you're sleeping badly following a death in the family or some other stressful event. A physician may suggest the short-term use of a sedative to help you sleep at night and thus cope better during the day and prevent development of a long-term sleep disorder.

It's not always easy for people to get evaluation and treatment for a sleep problem. Doctors trained in the United States receive less than two hours of instruction on this topic during four years of medical school. According to a survey conducted by the National Sleep Foundation, most primary care physicians do not routinely ask their patients about sleep. And while most of the physicians who took part in the survey admitted they had limited knowledge about sleep-related matters, more than half did not consult with an expert in sleep medicine. This puts the responsibility on you to seek out the help you need.

Sleep laboratory evaluation

Most people with sleep problems don't need to visit a sleep laboratory. Insomnia and circadian rhythm disorders, for example, can be diagnosed by a thorough history and physical examination. However, when a doctor suspects a sleep disorder such as narcolepsy (see "Narcolepsy"), periodic limb movement disorder (see "Movement disorders in sleep"), sleep apnea (see "Sleep apnea"), or one of the parasomnias (see "Sleepwalking and other parasomnias"), he or she may recommend formal sleep testing.

Fees depend on the level of testing required. Some people require a one-time consultation with a sleep specialist, which may run a few hundred dollars. Staying overnight in a sleep laboratory costs between $800 and $1,500. It's important to check with your insurance company in advance because reimbursement varies and may depend on your diagnosis.

The American Academy of Sleep Medicine has a listing of more than 700 accredited sleep disorder centers and more than 2,600 board-certified sleep specialists (see "Resources"). Some centers will make an appointment directly with you, while others require a physician referral. The center will request medical records and may send you a sleep questionnaire or diary to use before your visit. You may also be asked to change your sleep habits in certain ways before scheduling the visit. Sometimes these changes alone correct the problem.

Overnight sleep tests

When you spend the night in a sleep laboratory, you'll wear your own nightclothes and you can use a pillow from home. You can use your regular medications, but the clinicians will need to know what they are. The lab usually provides a regular bed in a private room with a bathroom attached. The room is kept as quiet as is possible.

Polysomnography patient Polysomnography technician Polysomnography is commonly performed in sleep labs to monitor patients' sleep. For this procedure, small electrodes, placed on the scalp and other parts of the body, take readings during the night. Lab staff examine the readings from a nearby control room.

After a technician sets up the sleep-monitoring equipment, you'll be left alone to relax until bedtime. Throughout the night, laboratory staff will monitor the instruments in a nearby control room. Some of the tests and equipment used include polysomnography, audio- and videotape, and daytime sleep tests.

Polysomnography. In this procedure, small wafer-thin electrodes and other sensors are pasted on specific body sites to take a variety of readings during the night. They may be placed on your scalp to track brain waves; under your chin to measure fluctuations in muscle tension (called an electromyogram or EMG); near your eyes to measure eye movements; near your nostrils to measure airflow; on your earlobe or finger to measure the amount of oxygen in your blood (using a device called an oximeter); on your chest or back to record heart rate and rhythm; on your legs to record twitches or jerks; and over your rib muscles or around the rib cage and abdomen to monitor breathing.

Readings are collected on a single printout (called a polysomnogram) and analyzed by a technician and physician. If a breathing problem is detected early on, you may be awakened and given treatment, such as CPAP (see "Treatments for apnea"), during the second half of the night. This allows the sleep experts to monitor how well the treatment works for you. Sometimes this process requires two nights. A standard polysomnogram cannot diagnose sleep-related epilepsy. If your doctor suspects that you may have a seizure disorder, you may undergo a full electroencephalogram (EEG) during the night.

Audio- and videotape. Audiotape equipment may be used to record snoring, talking during sleep, or other sounds. A video may also be taken to compare with the polysomnogram. This may show, for example, that you snore only when in a certain position. Signs of movement disorders (such as periodic limb movement disorder) or parasomnias will probably be apparent on the videotape.

Daytime sleep tests. Daytime sleep tests may be administered after a night in the sleep lab. The multiple sleep latency test measures how long it takes you to fall asleep while lying down in a quiet room and what stages of sleep occur during a brief nap. The procedure is usually repeated four or more times during the day at two-hour intervals. This test measures sleepiness and looks for signs of narcolepsy. Falling asleep within five minutes each time indicates extreme sleepiness.

In the maintenance of wakefulness test, which is less commonly used, you're given the opposite instructions: Try to stay awake. This ability is also affected by the degree of sleepiness. People are sometimes given both tests at different times.

How sleepy are you? Sleep specialists often use this measure, called the Epworth Sleepiness Scale, to gauge a patient's level of daytime sleepiness. Imagine yourself in the following situations, and then select your likelihood of dozing using the 0–3 scale below. Add up these numbers. If you score 10 points or more, consider seeing a physician for an evaluation. Scale: 0 = would never doze 1 = slight chance of dozing 2 = moderate chance of dozing 3 = high chance of dozing Situation: ______ Sitting and reading ______ Watching TV ______ Sitting inactive in a public place, like a theater or meeting ______ As a passenger in a car for an hour without a break ______ Lying down to rest in the afternoon ______ Sitting and talking to someone ______ Sitting quietly after lunch (when you've had no alcohol) ______ In a car while stopped in traffic

Home-based tests

Some sleep-monitoring equipment can be used at home. Physicians, however, disagree about whether the information collected is reliable enough to use for diagnosis and treatment. Portable recordings may be useful when polysomnography is not available and symptoms indicate that immediate treatment is needed, or when a patient is bedridden or medically unstable and cannot be moved. Home-based tests may also be used when a physician wishes to evaluate the effectiveness of treatment.

Apnea detectors. To detect breathing disturbances during sleep, a patient is sometimes equipped with apnea detectors that can measure heart rate, snoring sounds, body position, nasal airflow, and the amount of oxygen in the blood. Although these devices have been used to estimate how many people suffer from breathing disturbances, the information they provide isn't as accurate as sleep lab evaluations and may not be complete enough to diagnose and plan treatment for an individual. Most experts believe a sleep lab evaluation is required.

Wrist actigraphy. A wristwatch-sized monitoring device that automatically records arm or leg movements can be used to track periods of sleep and wakefulness at night. Although it cannot determine the stage of sleep, it can help clarify ambiguous aspects of a sleep diary — such as entries reporting long hours of sleep but exhaustion the next day — or assess the effectiveness of medical treatment. The actigraphy device may reveal that brief awakenings during the night are unknowingly disturbing sleep. In some studies, wrist actigraphy accurately determined whether a person was asleep almost 90% of the time.

The American Academy of Sleep Medicine recommends polysomnography as the best method for diagnosing sleep apnea and determining its severity. Portable home devices can miss mild apnea and other sleep disruptions, and they don't provide the sleep stage information that's needed to rule out other sleep disturbances. Accordingly, they should only be used when the patient's physician is familiar with the devices' benefits and limitations and has experience interpreting the results.

Organizations

American Academy of Sleep Medicine 1 Westbrook Corporate Center, Suite 920 Westchester, IL 60154 708-492-0930 www.aasmnet.org

This professional membership organization is dedicated to the advancement of sleep medicine and related research. The group's Web site includes information on sleep disorders as well as contact information for accredited sleep centers.

American Insomnia Association 1 Westbrook Corporate Center, Suite 920 Westchester, IL 60154 708-492-0930 www.americaninsomniaassociation.org

Provides resources for insomnia patients.

American Sleep Apnea Association 1424 K St. NW, Suite 302 Washington, DC 20005 202-293-3650 www.sleepapnea.org

This nonprofit organization offers information on sleep apnea via brochures, a newsletter, and videos. It also operates a network of approximately 200 support groups throughout the country.

Narcolepsy Network P.O. Box 294 Pleasantville, NY 10570 888-292-6522 (toll free) www.narcolepsynetwork.org

The Narcolepsy Network offers educational materials on narcolepsy, as well as referrals to accredited sleep centers and help in finding support groups.

National Sleep Foundation 1522 K St. NW, Suite 500 Washington, DC 20005 202-347-3471 www.sleepfoundation.org

This nonprofit foundation helps consumers find a sleep center near them and provides information on a variety of sleep topics.

Restless Legs Syndrome Foundation, Inc. 819 Second St. SW Rochester, MN 55902 507-287-6465 www.rls.org

This nonprofit organization distributes brochures and provides information on restless legs syndrome. It also publishes the quarterly newsletter NightWalkers and maintains a list of support groups located throughout the country.

Books

A Clinical Guide to Pediatric Sleep: Diagnosis and Management of Sleep Problems in Children and Adolescents Jodi Mindell, Ph.D., and Judith Owens, M.D. (Lippincott Williams & Wilkins, 2003, 314 pages)

Intended for physicians, but parents whose children have difficulty sleeping will also benefit from this book. It includes guidelines for parents as well as tips for dealing with nighttime fears, nightmares, and sleepwalking.

The Enchanted World of Sleep Peretz Lavie, Ph.D. (Yale University Press, 1998, 286 pages)

Includes information on sleep stages, the brain centers involved in sleep regulation, the reasons for dreaming, and the importance of sleep in maintaining good health. Interspersed with case histories, anecdotes, and personal reflections.

The Promise of Sleep William C. Dement, M.D., Ph.D., and Christopher Vaughan (Dell Books, 2000, 560 pages)

An overview of sleep research and sleep problems by a respected pioneer in sleep medicine. Provides information on common sleep disorders and their treatment.