DefinitionObstructive sleep apnea is a condition in which a person has episodes of blocked breathing during sleep.This article discusses obstructive sleep apnea in adults.See also:Central sleep apneaSleep disordersAlternative NamesSleep apnea - obstructive; Apnea - obstructive sleep apnea syndrome; Sleep-disordered breathingCauses, incidence, and risk factorsNormally, the muscles of the upper part of the throat help keep the airway open and allow air to flow into the lungs. Even though these muscles usually relax during sleep, the upper throat remains open enough to let air pass by.However, some people have a narrower throat area. When the muscles in their upper throat relax during sleep, their airway may completely close. This prevents air from getting into the lungs. Loud snoring and lab