Sleep apnea is a serious, potentially life-threatening condition that is far more common than generally understood. First described in 1965, sleep apnea is a breathing disorder characterized by brief interruptions of breathing during sleep. It owes its name to the Greek word, apnea, meaning, "want of breath." There are two types of sleep apnea: central and obstructive. Central sleep apnea, which is less common, occurs when the brain fails to send the appropriate signals to the breathing muscles to initiate respiration.
Obstructive sleep apnea is far more common and occurs when air cannot flow into or out of the person's nose or mouth although efforts to breathe continue.
In a given night, the number of involuntary breathing pauses or "apneic events" may be as high as 20 to 30 or more per hour. These breathing pauses are almost always accompanied by snoring between apnea episodes, although not everyone who snores has this condition. Sleep apnea can also be characterized by choking sensations. The frequent interruptions of deep, restorative sleep often lead to early morning headaches and excessive daytime sleepiness.
In normal conditions, the muscles of the upper part of the throat keep this passage open to allow air to flow into the lungs. These muscles usually relax during sleep, but the passage remains open enough to permit the flow of air. Some individuals have a narrower passage, and during sleep, relaxation of these muscles causes the passage to close, and air cannot get into the lungs. Loud snoring and labored breathing occur. When complete blockage of the airway occurs, air cannot reach the lungs.
Early recognition and treatment of sleep apnea is important because it may be associated with irregular heartbeat, high blood pressure, heart attack, and stroke.
Sleep apnea occurs in all age groups and both sexes, but is more common in men (though it may be under-diagnosed in women) and possibly young African Americans. It has been estimated that as many as 18 million Americans have sleep apnea. Four percent of middle-aged men and 2 percent of middle-aged women have sleep apnea along with excessive daytime sleepiness. People most likely to have or develop sleep apnea include those who snore loudly and also are overweight, or have high blood pressure, or have some physical abnormality in the nose, throat, or other parts of the upper airway. Sleep apnea seems to run in some families, suggesting a possible genetic basis.
Sleep Apnea. Last reviewed 11/07/2006
- American Psychiatric Association—Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Revised
- National Heart, Lung, and Blood Institute, National Institutes of Health
- National Institute of Neurological Disorders and Stroke, National Institutes of Health
- National Sleep Foundation
- National Institutes of Health—National Library of Medicine