Sleep apnea is a condition in which breathing temporarily stops dozens or even hundreds of times during a person's sleep. Its most notable symptoms are snoring, which is nearly always present, and excessive sleepiness during the day. The most common form of the disease is called obstructive sleep apnea, in which the upper airway in the throat becomes obstructed. Breathing stops or diminishes for periods of 10 seconds to a minute or more. So, a patient who has sleep apnea will briefly arouse from sleep, open the airway, and emit a big snort or loud snore.
Breathing then resumes normally until the person falls back asleep.
At that point, breathing stops again, and the process can repeat itself hundreds of times in a night. The patient wears a mask that fits over the nose. The mask is connected by an air hose to a machine, slightly smaller than a shoebox, that is kept near the bed. The machine takes air from the room, filters it and pumps it to a higher pressure that is transmitted through the nose to the back of the throat, literally splinting the throat open. Researchers aren't sure, but it's widely accepted that it involves the structure of the airway.