Apnea is defined as a cessation of oronasal airflow of at least 10 seconds in duration. When it occurs 30 or more times during a 7-hour period of nocturnal sleep, it is called obstructive sleep apnea (OSA) and requires immediate intervention to prevent it from becoming life-threatening.
In the most common form of the condition - obstructive apnea (also called upper airway apnea) - air stops flowing through the nose and mouth, but throat and abdominal breathing efforts are uninterrupted. The snoring that results is produced when the upper rear of the mouth (the soft palate and the cone-shaped tissue - the uvula - that descends from it) relaxes and vibrates as air passes in and out. This sets up an air current between the palate and the base of the tongue, resulting in snoring. Typically, the individual will wake up, emit a vigorous snort or grunt while gasping for air, then immediately fall back to sleep, only to repeat the cycle. In another form of the disorder, central apnea, both oral breathing and throat and abdominal breathing efforts are simultaneously interrupted. In a third type of apnea, mixed apnea, a brief period of central apnea is followed by a longer period of obstructive apnea. Sleep apnea can be recognized by a number of symptoms. Loud and intermittent snoring is one warning signal. The person who has sleep apnea may experience a choking sensation, early-morning headaches, or extreme daytime sleepiness as well. His bed partner or roommate might comment on his excessive body movements or his snorting or gasping for breath during sleeping. If the condition is suspected, it should be reported to a physician, who may recommend evaluation by a specialist in sleep disorders. Since sleeping pills may be harmful for people with sleep apnea, they should not be taken if the condition is suspected.
Sleep apnea is believed to affect at least 1 out of every 200 Americans - 70 to 90 percent are men, mostly middle-aged and usually overweight. But the condition can afflict both men or women at any age.
People with this disorder actually may stop breathing while asleep - even hundreds of times - without being aware of the problem. During an apnea attack, the snorer may seem to gasp for breath, and the blood may become abnormally low. In severe cases, a sleep apnea victim may actually spend more time not breathing than breathing and may be at risk for death.
Polysomnography, a technique used to diagnose obstructive sleep apnea, records the number and duration of apnetic episodes, determines the stage of sleep and oxygen saturation and observes when the patient awakens.