Sleep Apnea Characteristics
Sleep apnea is characterized by a number of involuntary breathing pauses or "apneic events" during a single night's sleep - may be as many as 20 to 30 or more events per hour. These events are almost always accompanied by snoring between apnea episodes (although not everyone who snores has sleep apnea). 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. With each arousal, a signal is sent from the brain to the upper airway muscles to open the airway; breathing is resumed, often with a loud snort or gasp. Frequent arousals, although necessary for breathing to restart, prevent a person from getting enough restorative, deep sleep.