American Medical Association Family Medical Guide - American Medical Association [384]
The most common type of sleep apnea, called obstructive sleep apnea, is caused by an overly relaxed or sagging base of the tongue, uvula (the small piece of tissue that hangs from the middle of the back of the throat), or soft palate (roof of the mouth). These sagging tissues obstruct air flow to and from the person’s windpipe. Using alcohol or sleeping pills worsens sleep apnea by making the airway tissue more likely to sag during sleep. In the less common type of sleep apnea called central sleep apnea, the brain fails to send the required signals to the breathing muscles to continue regular inhalation and exhalation during sleep.
Sleep apnea occurs in people of all ages, including children, and is more common in men than in women. Overweight people are most likely to develop sleep apnea, although with age the connection between sleep apnea and obesity is less pronounced. Other people who are at risk for sleep apnea include those who have a structural abnormality of the nose or throat or other parts of the upper airway. The disorder seems to run in families. It has been linked to some cases of sudden infant death syndrome (see page 388). People with sleep apnea are often totally unaware that they have the disorder. Their family or friends suspect sleep apnea after hearing excessive snoring or seeing the person struggle to breathe during sleep.
Symptoms
People who have sleep apnea snore loudly between pauses in breathing (although not everyone who snores has sleep apnea) and may experience choking sensations or awaken with shortness of breath. The disorder often causes early morning headaches and daytime sleepiness. Chronic lack of sleep from sleep apnea may cause depression, irritability, learning and memory difficulties, and sexual problems. Sleep deprivation also places a person at risk of vehicle collisions and work-related accidents.
Sleep apnea can cause the heart to beat irregularly. It can contribute to high blood pressure and heart failure because the heart beats harder in the long term trying to make up for the chronically low oxygen levels. In people who already have heart disease (see page 558), sleep apnea can contribute to heart attacks.
Snoring
Snoring occurs when tissue at the back of your throat—the tonsils, adenoids, back of the tongue, or uvula—vibrates as air travels over it while you breathe during sleep. When this tissue becomes enlarged or when it develops poor muscle tone (which often results from excessive, long-term alcohol consumption), snoring is more likely to occur. Swollen and inflamed nasal passages resulting from a cold or allergies can also cause temporary snoring. Most snoring is not serious, but heavy or loud snoring can be a sign of sleep apnea.
If your snoring disrupts your sleep or the sleep of other people, see your doctor. The remedy may be as simple as changing your sleep position or raising the head of your bed. Losing weight may also help. Taking sleeping pills, drinking alcohol, or smoking can cause the tissue at the back of your throat to relax during sleep, increasing the chances that you will snore.
Diagnosis
Because disturbed sleep can have many causes, doctors use two specific tests to diagnose sleep apnea and determine its severity. Both are conducted overnight in a sleep center. The first test, polysomnography, measures a variety of body functions during sleep, including eye movement, muscle activity, the electrical activity of the brain, heart rate, and blood oxygen levels. Polysomnography also indicates when the person enters and leaves different stages of sleep. The second test, the multiple sleep latency test, determines how fast the person falls asleep.