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Am Fam Physician. 1999;59(4):937-944

See editorial on page 762.

Normal sleep is required for optimal functioning. Normal wakefulness should be effortless and free of unintended sleep episodes. Problem sleepiness is common and occurs when the quantity of sleep is inadequate because of primary sleep disorders, other medical conditions or lifestyle factors. Medications and substances that disturb sleep, such as caffeine and nicotine, or those that have sedating side effects, may also cause problem sleepiness. This condition can lead to impairment in attention, performance problems at work and school, and potentially dangerous situations when the patient is driving or undertaking other safety-sensitive tasks. However, problem sleepiness is generally correctable when it is recognized. Asking a patient and his or her bed partner about the likelihood of drowsiness or of falling asleep during specific activities, as well as questions that uncover factors contributing to the sleepiness, helps the physician to recognize the disorder. Accurate diagnosis of specific sleep disorders may require evaluation by a specialist. The primary care physician is in an ideal position to identify signs and symptoms of problem sleepiness and initiate appropriate care of the patient, including educating the patient about the dangers of functioning while impaired by sleepiness.

Patients who are frequently sleepy at inappropriate times may have “problem sleepiness” and not realize it. Problem sleepiness occurs when patients don't get enough sleep because of primary sleep disorders (such as obstructive sleep apnea, insomnia, restless legs syndrome or narcolepsy), other medical conditions (such as chronic bronchitis or congestive heart failure) or lifestyle factors (such as shift work).1 Sleepy persons exhibit levels of impairment that range from poor functioning at home, school or work, to potentially life-threatening automobile crashes and industrial accidents.

Performance impairment caused by sleepiness is comparable to that caused by alcohol intoxication.2 Patients with problem sleepiness may complain of having difficulty with concentration, fatigue and emotional lability. The primary care physician has a central role in the detection and correction of problem sleepiness. Incorporating sleep-related questions into the history-taking process will aid in the initial assessment. The physician also should educate patients about the signs and dangers of problem sleepiness, the possible underlying causes and the importance of obtaining adequate sleep for optimal functioning.

Consequences of Problem Sleepiness


The National Highway Traffic Safety Administration estimates that approximately 56,000 crashes per year are the result when drivers fall asleep “at the wheel.”3 Persons with untreated sleep disorders such as sleep apnea, narcolepsy or insomnia have higher rates of automobile crashes than do other drivers.4,5 In a survey of drivers in New York state,6 approximately 25 percent reported they had fallen asleep at the wheel at some time. Fall-asleep crashes are especially common in young male drivers.7


In addition to placing young people at high risk for automobile crashes, problem sleepiness can impair learning, perceptual skills and memory,8,9 which may lead to poor school performance and grades. Mood, attention and behavior deteriorate in adolescents and young adults when they have not had adequate amounts of sleep.10 These changes may interfere with a teenager's ability to cope with daily stressors.


Sleepiness in the workplace contributes significantly to performance errors and increases the risk of accidents. Sleepiness has contributed to serious incidents in industrial operations, nuclear power plants and all modes of transportation.11

Causes of Problem Sleepiness

In all people, sleepiness is regulated by two primary processes: the body's circadian rhythm, which causes an increase in sleepiness twice during a 24-hour period (in general, during the hours between midnight and 7 a.m. and for a brief period in the midafternoon, between 1 p.m. and 4 p.m.); and the physiologic need for sleep, which is increased by sleep loss and sleep disruption.

The need for sleep and the circadian rhythm interact to determine a person's levels of sleepiness and alertness.12 People with disturbances of either of these sleep-regulating mechanisms can exhibit problem sleepiness, with the most common causes being primary sleep disorders, other medical conditions that disrupt sleep, drugs and lifestyle.


Obstructive Sleep Apnea. Obstructive sleep apnea, a potentially life-threatening disorder, is produced by a narrowing or collapsing of the upper airway during sleep that restricts or prevents breathing.13 Repeated episodes of airway collapse throughout the night disrupt and fragment sleep, and may produce hypoxemia and other cardiovascular stress. Sleep apnea has been suspected of contributing to myocardial ischemia and myocardial infarction in patients with coronary artery disease.14

Sleep apnea is found in approximately 4 percent of middle-aged men and 2 percent of middle-aged women.15 The prevalence is even higher among elderly patients.16 Symptoms of obstructive sleep apnea include chronic, loud snoring, gasping or choking episodes during sleep, excessive daytime sleepiness, drowsiness while driving, automobile- or work-related accidents, and personality changes or cognitive difficulties. Indicators of obstructive sleep apnea are obesity, a thick neck, systemic hypertension and nasopharyngeal narrowing. The diagnosis of obstructive sleep apnea is confirmed by polysomnography. The severity of symptoms dictates the urgency of the need for testing.

Insomnia. Patients with insomnia complain that sleep is difficult to initiate or maintain, or that the sleep they get is neither refreshing nor restorative.5,17 Insomnia is the most prevalent sleep-related complaint; approximately 30 percent of American adults report occasional insomnia, and nearly 10 percent report chronic insomnia.5,18 Women report insomnia more frequently than do men,5,19,20 and insomnia complaints increase with age.20,21 Some patients with insomnia have problem sleepiness.18,22

Insomnia is classified by the duration of symptoms. Acute insomnia is usually the result of a stressful life event or a change in sleep environment or sleep schedule. Chronic insomnia may result from medical conditions, psychiatric disorders or other causes.5 Thus, a careful sleep history is required for an accurate diagnosis.

Restless Legs Syndrome and Periodic Limb Movements in Sleep. The symptoms of restless legs syndrome are commonly reported and include sensations of creeping, crawling, pulling and tingling, which cause an irresistible urge to move the legs. These symptoms usually occur before sleep onset, making it difficult for the patient to fall asleep. Patients with restless legs syndrome often have coexisting periodic limb movements in sleep. The latter condition is characterized by episodes of repetitive, stereotyped limb (usually leg) movements occurring during sleep that may disturb the patient or the bed partner.23 The limb movements are often associated with partial or complete awakening, although patients are usually unaware of either their movements or the arousals. The prevalence of periodic limb movements in sleep increases with advancing age; as many as one third of patients older than 60 years may have this condition.24

Patients with restless legs syndrome and periodic limb movements in sleep may have problem sleepiness or nonrefreshing sleep because of frequent arousals (partial awakenings that may not be remembered) during the night or because they have difficulty falling asleep. The diagnosis of restless legs syndrome is based on history; there is no specific laboratory test. In contrast, periodic limb movements in sleep can be detected by polysomnography.

Narcolepsy. Narcolepsy is a chronic sleep disorder that produces severe problem sleepiness. The primary symptoms of narcolepsy are excessive and overwhelming daytime sleepiness—even after adequate nocturnal sleep—and cataplexy (sudden episodes of muscle weakness triggered by emotional reactions such as laughter, anger or fear). Other classic symptoms of narcolepsy include sleep paralysis (a temporary inability to talk or move on falling asleep or awakening) and hypnagogic hallucinations (vivid, frightening, dreamlike experiences that occur while dozing or falling asleep).

Narcolepsy is often misdiagnosed. Symptoms usually first become evident during adolescence and young adulthood, commonly before the third decade of life. Narcolepsy can also occur in children. A definitive diagnosis of narcolepsy usually requires objective testing and evaluation by a sleep specialist.


Persons with medical conditions such as chronic bronchitis and asthma have more problems initiating and maintaining sleep than do healthy people.2527 Persons who have congestive heart failure may have a higher prevalence of periodic limb movements in sleep (with associated arousals) and consequently may experience daytime sleepiness.28 Persons with severe congestive heart failure who also have Cheyne-Stokes respirations have sleep fragmentation and nocturnal hypoxemia leading to problem sleepiness.29 Chronically painful conditions such as rheumatoid arthritis, back pain and sickle cell disease can also disrupt sleep and lead to problem sleepiness.3032


Prescription and over-the-counter drugs, as well as caffeine, alcohol and nicotine, can have substantial effects on sleep and sleepiness. For example, long-acting benzodiazepines have residual sedative effects that contribute to daytime sleepiness33; beta blockers can cause difficulty falling asleep and increase the number of nighttime awakenings34; and theophylline, even when taken at low therapeutic dosages, has been shown to disrupt sleep in some people.35

Caffeine can fragment sleep. The half-life of caffeine is between three and seven hours, so even coffee consumed during the day may be an important cause of sleeplessness at night, thereby causing sleepiness the next day.36 While alcohol shortens the time it takes to fall asleep and is often ingested by patients for this reason, it increases sleep disruption in the latter part of the night.34 Nicotine can disrupt sleep and reduce total sleep time. Smokers report significantly more daytime sleepiness and minor accidents than do nonsmokers, especially in younger age groups.37


The need for sleep varies among individuals and, because of this, it is difficult to recommend a specific quantity of sleep for all persons. When adults are allowed to sleep without restriction, the average time slept is eight to eight and one-half hours.38,39 Chronic lack of sleep can lead to a cumulative sleep debt and problem sleepiness.40,41 In some patients, problem sleepiness resolves when sleep duration increases. If problem sleepiness does not resolve with added sleep, other causes should be considered.

Shift Workers. Approximately 20 to 25 percent of the American work force is engaged in some form of shift work.42 Most shift workers complain of difficulty falling or staying asleep, or problem sleepiness.43,44 The sleepiness of shift workers is related to both insufficient sleep and the displaced timing of sleep and wakefulness.45 The adverse effects of shift work differ among individuals and may vary with age; younger workers cope better than older workers.46

Shift workers are at high risk for motor vehicle crashes; in one study, 20 percent had a traffic accident or a “near miss” in the preceding 12 months because of sleepiness on the drive home from work.47 Consequently, shift workers should be advised about their increased risk for accidents. Because of their vulnerability, it is particularly important to assess these persons for inadequate sleep duration and coexisting sleep disorders, which magnify the sleepiness caused by shift work.

Adolescents. A significant proportion of young people report symptoms of problem sleepiness that include difficulty getting up for school, falling asleep in school or struggling to stay awake while doing homework.48 Such symptoms may be the result of inadequate sleep. Adolescents need more sleep than adults do and in many, the amount of sleep needed is at least nine hours per night.49,50 In addition, the circadian timing system may change during puberty, resulting in a tendency for adolescents to stay up later and sleep in later.5154

Identifying Patients with Problem Sleepiness

Patients may underestimate their own degree of sleepiness. Questions regarding specific sleep/wake habits and activities, as well as input from family members, can reveal significant signs of problem sleepiness. When assessing whether a patient is getting enough sleep, it is best to ask about bedtimes and rising times, because asking how long the patient sleeps is likely to yield an inaccurate estimate. Comparing sleep quantity on days off versus work days may be helpful. Patients who sleep several hours longer on their days off (by sleeping in or napping) may not be getting enough sleep during the work week. They may describe feeling more alert on their days off.

Identification of problem sleepiness is more effectively accomplished by asking a patient about the likelihood of feeling drowsy or of falling asleep during specific activities, rather than by a general inquiry regarding the degree of sleepiness. Many patients with chronic problem sleepiness do not appreciate how sleepy or impaired they may be, but they can usually indicate the circumstances under which they experience drowsiness and their likelihood of falling asleep in routine situations, even if they do not consider these sleep attacks abnormal. Table 1 lists examples of questions that can be included in an interview with a patient to identify problem sleepiness and possible contributing factors. Accurate diagnosis of specific sleep disorders will require further exploration and, possibly, evaluation by a sleep specialist. Table 2 lists organizations that can provide more information on problem sleepiness.

Ask the patient about signs of excessive sleepiness:
• Does the patient report dozing off or having difficulty staying awake during routine tasks, especially while driving?
Feeling drowsy or accidentally falling asleep while performing routine tasks is not normal and indicates an elevated need for sleep that can be very dangerous if it occurs while the patient is driving or performing other safety-sensitive activities.
• Does the patient complain of having difficulties or accidents at work, school, social activities or home because of a poor attention span?
Sleepiness has a number of effects, but its most pervasive consequences are decreased ability to pay attention, becoming forgetful or drowsy, and falling asleep accidentally.
• Does the patient complain of sleepiness or of getting nonrefreshing sleep, or is the patient's sleepiness frequently noted by others?
Some patients may report feeling sleepy at inappropriate times and places; others may report that family members, friends and coworkers have commented on or expressed concern about their sleepiness.
• Does the patient nap on most days or more often than once a day?
While a brief nap in the afternoon can be a normal part of the sleep-wake cycle of some patients, frequent napping, whether intentional or unintentional, can be a sign of problem sleepiness.
Ask the patient about signs of sleep disorders:
• Does it take the patient more than 30 minutes to fall asleep at night? Are there awakenings during the night? Is there unwanted early morning waking? (Relates to insomnia.)
• Does the bed partner report that the patient's legs or arms jerk during sleep? (Relates to periodic limb movements in sleep.)
• Does the patient report “creeping, crawling feelings” in the legs? (Relates to restless legs syndrome.)
• Does the patient (or bed partner) complain of loud snoring, gasping, choking, or stopping breathing during sleep? (Relates to obstructive sleep apnea.)
• Does the patient (or family) describe cataplexy (sudden muscle weakness in response to emotional reactions), hypnagogic hallucinations (vivid, dreamlike experiences while falling asleep or dozing) or sleep paralysis (temporary inability to talk or move when falling asleep or awakening)? (Relates to narcolepsy.)
Ask the patient about the quantity and quality of sleep:
• Is the patient a shift worker? What are the work hours? Is the patient an adolescent?
Shift workers, persons working prolonged hours and adolescents are at increased risk for inadequate sleep and problem sleepiness.
• At what time does the patient get up and go to bed, on weekdays and weekends?
Problem sleepiness from inadequate sleep during the work or school week can be indicated by differences of 2 hours or more between typical weekday sleep durations and typical weekend durations.
• Does the patient use caffeine, tobacco, alcohol or over-the-counter and prescription medications?
Reliance on common stimulants in an attempt to remain awake or alert can mask problem sleepiness and exacerbate it through sleep disruption. Alcohol can disrupt sleep, and preexisting sleepiness heightens the sedative effects of alcohol, making a sleepy patient who consumes a small amount of alcohol more susceptible to performance impairment and driving accidents than a well-rested patient who consumes the same amount. Prescription medications can produce daytime sleepiness or disrupt sleep.
• Is the sleep environment conducive to sleep in terms of noise, interruptions, temperature and light?
Some adult and adolescent patients may not be aware that problem sleepiness can be caused by disruptions that occur in an environment unconducive to sleep.
• Does the patient have a medical condition, chronic pain or other such cause of sleep difficulties?
Problem sleepiness can be a result of sleep disruption caused by medical conditions such as asthma, congestive heart failure, rheumatoid arthritis, back pain and sickle cell disease.
National Center on Sleep Disorders
Research, National Institutes of Health
Two Rockledge Centre, Suite 10038
6701 Rockledge Dr., MSC 7920
Bethesda, MD 20892-7920
Telephone: 301-435-0199
Fax: 301-480-3451
National Heart, Lung, and Blood
Institute Information Center
P.O. Box 30105
Bethesda, MD 20824-0105
Telephone: 301-251-1222
Fax: 301-251-1223
Internet address:
Supports research, scientist training, dissemination of health information and other activities focused on sleep and sleep disorders. Also coordinates sleep research activities with other federal agencies and with public sand nonprofit organizations.
Acquires, analyzes, promotes, maintains and disseminates health promotion and disease prevention Program materials and educational information related to sleep disorders and sleep-disordered breathing. Offers a list of available publications and brochures.

Management of Problem Sleepiness

Problem sleepiness can occur in any age group. Direct questions of the kind highlighted in Table 1 should be asked to identify inappropriate sleepiness. Family members also may be able to help clarify the situation. Patients need to be aware of the obligatory nature of sleep and its importance for optimal functioning. For those with problem sleepiness caused by lifestyle, emphasis on obtaining adequate sleep is appropriate. Because of the inattention and inadvertent onset of sleep that can result from sleepiness, it is extremely important to educate the patient about the dangers of driving while sleepy.

Accurate identification of all causes of the patient's problem sleepiness is crucial for effective treatment. For example, an adolescent may have narcolepsy in addition to inadequate sleep, causing problem sleepiness. Similarly, a shift worker may have obstructive sleep apnea in addition to a sleep/wake schedule problem.

All patients, and especially young people, should be advised that preexisting sleepiness heightens the sedative effects of alcohol. Thus, a sleepy person consuming a small amount of alcohol is much more susceptible to sedation, impaired performance and vehicle crashes than a well-rested person who consumes the same amount of alcohol.5557

Stimulants do not play a major role in the treatment of problem sleepiness (except for patients with narcolepsy), and they do not serve as a substitute for sleep. The regular use of stimulants by patients may be a clue to the existence of an underlying sleep disorder or problem sleepiness.


Sleep disorders are chronic, necessitating long-term management and monitoring. Primary care physicians play an important role in case-finding, as well as management of patients with sleep disorders.58 Incorporating a sleep history into the general review of systems can be useful in identifying these patients (Table 1). Patients with severe symptoms, such as falling asleep while driving, generally require a sleep study, interpreted by someone with expertise in sleep disorders, for accurate diagnosis.59

In patients with sleep apnea, treatment options range from behavioral therapies to oral/dental appliances and surgical interventions. Many patients are treated with nasal continuous positive airway pressure (CPAP), in which a mask is worn over the nose during sleep; pressure from an air blower forces air through the nasal passages, preventing airway collapse.

A broad treatment plan for insomnia may include behavioral therapies alone or a combination of behavioral and pharmacologic treatments.60 Short-term use of short-acting hypnotics has been shown to be effective in reducing problem sleepiness associated with acute insomnia. However, long-term use of hypnotics for insomnia remains controversial. Lower dosages of short-acting agents should be prescribed for older patients.61 In the treatment of obstructive sleep apnea, hypnotics are counterproductive and worsen symptoms.

Pharmacotherapy for restless legs syndrome and periodic limb movements in sleep may include benzodiazepines, dopaminergic agents or opioids. In mild cases of restless legs syndrome, patients may relieve symptoms by massaging the legs, exercising and eliminating alcohol and caffeine intake.

Treatment of narcolepsy, once the diagnosis has been confirmed by a sleep specialist, includes central nervous system stimulants for excessive daytime sleepiness, as well as anti-cholinergics and antidepressant agents for cataplexy. Scheduled naps are an important adjunct to drug therapy.

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