What is Sleep Apnea?
The Greek word "apnea" literally means "without breath." There are three types of apnea: obstructive, central, and mixed; of the three, obstructive is the most common. Despite the difference in the root cause of each type, in all three, people with untreated sleep apnea stop breathing repeatedly during their sleep, sometimes hundreds of times during the night and often for a minute or longer.
Sleep apnea (or sleep apnoea in British English) is a sleep disorder characterized by pauses in breathing during sleep. Each episode, called an apnea, lasts long enough so that one or more breaths are missed, and such episodes occur repeatedly throughout sleep.[1]  The standard definition of any apneic event includes a minimum 10-second interval between breaths, with either a neurological arousal (a 3-second or greater shift in EEG  frequency, measured at C3, C4, O1, or O2) or a blood oxygen desaturation of 3–4% or greater, or both arousal and desaturation. Sleep apnea is diagnosed with an overnight sleep test called a polysomnogram, or a "sleep study".