Breathing-Related Sleep Disorder

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Breathing-Related Sleep Disorder



Causes and symptoms








Breathing-related sleep disorder is marked by sleep disruption from abnormal breathing during sleep. The most common complaint of individuals with breathing-related sleep disorder is excessive daytime sleepiness, brought on by frequent interruptions of nocturnal, or nighttime, sleep. A less frequent complaint is insomnia or inability to sleep. About two-thirds with this disorder experience daytime sleepiness and one-third from an inability to sleep.

Mental health professionals use the Diagnostic and Statistical Manual of Mental Disorders, also known as the DSM to diagnose mental disorders. In the 2000 edition of this manual (the fourth edition, text revision, also known as DSM-IV-TR), breathing-related sleep disorder is listed as one of several different primary sleep disorders. Within the category of primary sleep disorders, it is classified as one of the dyssomnias, which are characterized by irregularities in the quality, timing, and amount of sleep.

The DSM-IV-TR lists three types of breathing-related sleep disorder: obstructive sleep apnea syndrome (the most common type), central sleep apnea syndrome, and central alveolar hypoventilation syndrome.


The most common feature of any breathing-related sleep disorder is interruption of the person’s sleep, leading to excessive daytime sleepiness. When the regular nighttime sleep of individuals is frequently interrupted, sleepiness at other times of the day is the usual result. People with breathing-related sleep disorder often find that they feel sleepy during relaxing activities such as reading or watching a movie. With extreme cases, those with this condition may feel so sleepy that they fall asleep during activities that require alertness, such as talking, walking, or driving.

Other people with breathing-related sleep disorder report having insomnia, or the inability to sleep. Patients also find that their sleep does not refresh them; they may awaken frequently during sleep, or have difficulty breathing while sleeping or lying down.

The two sleep apnea syndromes that are listed as subtypes of breathing-related sleep disorder are characterized by episodes of airway blockage or breathing cessation during sleep. Sleep apnea is potentially deadly. Central alveolar hypoventilation syndrome is distinguished from the other two subtypes of breathing-related sleep disorder by the fact that shallow breathing causes the reduced oxygen content of the blood. The alveoli, which are the tiny air sacs in the lung tissue, cannot oxygenate the blood efficiently because those with this disorder are not breathing deeply enough. Shallow breathing often occurs when people are awake and is common in severely overweight individuals.

Causes and symptoms


Many people with the obstructive sleep apnea syndrome subtype of breathing-related sleep disorder are overweight. The symptoms often grow worse as their weight increases. People who have obstructive sleep apnea and are not overweight often have breathing passages that are narrowed by swollen tonsils, abnormally large adenoids, or other abnormalities of the various structures of the mouth and throat. The fundamental underlying cause appears to be a narrow or collapsible airway with a loss of muscle tone in the airway during sleep.

Central sleep apnea syndrome is often associated with cardiac or neurological conditions affecting airflow regulation. It is a disorder that occurs most frequently in elderly patients.

Patients diagnosed with central alveolar hypoventilation syndrome experience a breathing impairment related to abnormally low arterial oxygen levels.


Obstructive sleep apnea syndrome, which is the most common type of breathing-related sleep disorder, is marked by frequent episodes of upper airway obstruction during sleep. Patients with this syndrome alternate between loud snores or gasps and silent periods that usually last for 20-30 seconds. The snoring is caused by the partial blockage of the airway. The silent periods are caused by complete obstruction of the airway, which makes the patient’s breathing stop. These periods of breathing cessation can last between 10 seconds and one minute.

Obstructive sleep apnea syndrome is also common in children with enlarged tonsils. The symptoms of any breathing-related sleep disorder in children are often subtle and more difficult to diagnose. Children under five years are more likely to demonstrate nighttime symptoms such as apnea and breathing difficulties. Children over five years are more likely to demonstrate daytime symptoms such as sleepiness and attention difficulties.

People with central sleep apnea syndrome experience periods when the oxygenation of blood in the lungs temporarily stops during sleep, but they do not suffer airway obstruction. Although these patients may snore, their snoring is usually mild and not a major complaint.

Central alveolar hypoventilation syndrome is characterized by excessive sleepiness and insomnia.


As of 2007, it has been estimated that between 7 and 18 million Americans have some kind of breathing-related sleep disorder. Rates are higher among people who are overweight, obese, or elderly. The majority of patients with the obstructive sleep apnea type of breathing-related sleep disorder are overweight, middle-aged males. Four percent of middle-aged men and 2% of middle-aged women meet the criteria for obstructive sleep apnea. Among children the male-to-female ratio is 1:1. Prevalence of breathing-related sleep disorder among children peaks between two and eight years of age.


A diagnosis of breathing-related sleep disorder usually requires a thorough physical examination of the patient. The patient may be referred to an otorhinolaryngologist (a doctor who specializes in disorders of the ear, nose, and throat) for a detailed evaluation of the upper respiratory tract. The physical examination is followed by observation of the patient in a sleep clinic or laboratory. Breathing patterns, including episodes of snoring and apnea, are evaluated when the patient is connected to a device called a polysomno-gram. The polysomnogram uses a set of electrodes to measure several different body functions associated with sleep, including heart rate, eye movements, brain waves, muscle activity, breathing, changes in blood oxygen concentration, and body position. Interviews are also conducted with the patients and their partners.

To meet criteria for the diagnosis of breathing-related sleep disorder, patients must experience interruptions of sleep leading to insomnia or excessive sleepiness that have been determined to result from one of the following sleep-related breathing conditions: obstructive sleep apnea syndrome, central sleep apnea syndrome, or central alveolar hypoventilation syndrome.

The disturbance in sleep must also not be attributed to another mental disorder or by a general medical condition not related to breathing.

The disturbance in sleep must not be due to the direct effects on the body of a prescription medication or drug of abuse.


Weight loss is a key to effective treatment of overweight people with breathing-related sleep disorder. It is often considered the first step in treating any disorder involving sleep apnea. Increased exercise and reduced-calorie diets are the most important components of an effective weight loss regimen.

Another approach to addressing sleep apnea is a postural change during sleep, called “positional therapy.” The U.S. Food and Drug Administration (FDA) has approved a pillow that is supposed to aid in preventing the sleeper from assuming a supine (on the back) position, a position that may worsen sleep apnea. In addition, postural alarms are also being marketed to warn the sleeper, but many people try home-based approaches to ensuring that they do not flip onto their backs during sleep. One study has found that sleeping on the back with the torso elevated may result in reduced apneas, but recommended that patients trying this option use foam pillows rather than soft pillows, which can push the chin onto the chest and worsen apnea.

Oral appliances may be effective for people who have mild apnea. The most common of these is the mandibular advancement device (also called MAD), which pushes the lower jaw forward, keeping the airway open.

Continuous positive airway pressure therapy, also known as CPAP therapy, is a popular form of treatment for the obstructive sleep apnea subtype of breathing-related sleep disorder. CPAP therapy, which has been in use since 1981, involves the use of a high-pressure blower that delivers continuous air flow to a mask worn by the patient during sleep. The airflow from the CPAP blower is often very effective in reducing or eliminating sleep apnea episodes. CPAP treatment is, however, inconvenient and somewhat noisy for anyone who must share a bedroom with the patient. Patients do not always comply with this form of treatment; a 2004 study indicated that about 25% of patients who are treated with CPAP therapy stop using it within a year. A couple of alternative forms of CPAP may improve compliance by improving comfort, including bi-level positive airway pressure, which has two sets of air pressures that it delivers, one for exhalation and one for inhalation, to make using the device more comfortable. Also, a more recent introduction is the C-Flex, which provides flexible positive airway pressure, alternating pressures for inhalation and exhalation on a breath-by-breath basis. The company that produces the C-Flex received FDA permission to market its product in 2004. CPAPs, as medical devices, must be obtained through a doctor’s prescription.

There are no medications that directly target sleep apnea.

Surgery to relieve airway obstruction may be performed in some cases. If the airway obstruction is related to anatomical structures that narrow the airway, surgical reshaping of the soft palate and uvula (a small, conical-shaped piece of tissue attached to the middle of the soft palate) may be performed. Another surgical procedure that is sometimes conducted on very obese patients with obstructive sleep apnea is a tracheostomy, or an artificial opening made in the windpipe. This operation has a number of unpleasant side effects, however, and so is usually reserved for patients whose breathing-related disorder is life-threatening.

Patients with sleep apnea are advised to abstain from alcohol and sedative medications, which are often given to patients who display any type of sleeping irregularities. Alcohol and sedatives often increase the likelihood of upper airway problems during sleep.


Breathing-related sleep disorder often has a gradual long-term progression and a chronic course. For this reason, many people have the disorder for years before seeking treatment. For many, symptoms worsen during middle age, causing people to seek treatment at that point.

Successful treatment of other conditions, such as obesity, the common cardiovascular and cerebrovascular comorbidities, or enlarged tonsils in children, often aids in the treatment of breathing-related sleep disorder. Weight loss often leads to spontaneous resolution of the disorder. Because depression has been found at high rates among people with sleep apnea (as high as 64% in some studies), any assessments should evaluate for the presence of depression to aid in improving the prognosis.


Because overweight people are more likely to develop the more common obstructive sleep apnea type of breathing-related sleep disorder, a good preventive measure is effective weight management. Good general health and treatment of related physiological conditions are also effective in preventing the disorder.


Alveolar —Pertaining to alveoli, which are tiny air sacs at the ends of the small air passages in the lungs.

Apnea —A brief suspension or interruption of breathing.

Dyssomnia —A type of sleep disorder characterized by a problem with the amount, quality, or timing of the patient’s sleep.

Hypoventilation —An abnormally low level of blood oxygenation in the lungs.

Polysomnogram —A machine that is used to diagnose sleep disorders by measuring and recording a variety of body functions related to sleep, including heart rate, eye movements, brain waves, muscle activity, breathing, changes in blood oxygen concentration, and body position.

Syndrome —A group of symptoms that together characterize a disease or disorder.

Tracheostomy —A surgical procedure in which an artificial opening is made in the patient’s windpipe to relieve airway obstruction.

See alsoCircadian rhythm sleep disorder; Obesity.



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American Sleep Apnea Association. 1424 K Street NW, Suite 302, Washington DC 20005. <>.

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Ali Fahmy, PhD
Emily Jane Willingham, PhD