Sleep apnea is one of several sleep disorders. Sleep apnea refers to repeated episodes of no breathing for at least 10 seconds during sleep (apneic episodes).

Sleep apnea usually is caused by blockage (obstruction) in the nose or mouth (upper airway). The blockage may be caused by defects of the nose, larger-than-average soft tissues in the throat, or enlarged tonsils and adenoids.

Sleep apnea may also be caused by abnormal electrical signals from the brain to the muscles that control breathing (central sleep apnea). The cause of this type of apnea usually is unknown. However, central sleep apnea may also occur with other conditions such as stroke, brain tumors, and infections of the brain.

The most common symptoms of sleep apnea in adults are loud snoring and excessive daytime sleepiness. Almost all people who have sleep apnea snore, but not all people who snore have sleep apnea. Other signs and symptoms of sleep apnea include:

• Episodes of not breathing (apnea) during sleep. This may occur from as few as 5 times an hour (mild apnea) to more than 50 times an hour (severe apnea).
• Restless tossing and turning during sleep.
• Nighttime choking spells, sweating, and chest pain.
• Waking with an unrefreshed feeling after sleep, difficulty thinking, poor memory, irritability, tiredness, and personality changes.
• Reduced sex drive.
• Morning headaches.
• Bed-wetting.
• Heartburn or a sour taste in the mouth at night.
• Dry mouth or sore throat in the morning.