Sleep apnea occurs in all age groups and both genders. It is more common in men, although it may be under diagnosed in women and young African-Americans. It is estimated that as many as 18 million Americans have sleep apnea. It is a breathing disorder characterized by brief interruptions of breathing during sleep. Central sleep apnea is less common than obstructive sleep apnea .
Sleep apnea seems to run in some families, suggesting a possible genetic basis.
Sleep apnea may also be characterized by choking sensations. The frequent interruptions of deep, restorative sleep often lead to early morning headaches and excessive daytime sleepiness. During the apneic event, the person is unable to breathe in oxygen and to exhale carbon dioxide, resulting in low levels of oxygen and increased levels of carbon dioxide in the blood. The reduction in oxygen and increase in carbon dioxide alert the brain to resume breathing and cause an arousal. Frequent arousals, although necessary for breathing to restart, prevent a person from getting enough restorative, deep sleep.