What Causes Sleep Apnea?

Sleep apnea happens when enough air cannot move into your lungs while you are sleeping. When you are awake, and normally during sleep, your throat muscles keep your throat open and air flows into your lungs. In obstructive sleep apnea, however, the throat briefly collapses, causing pauses in your breathing. With pauses in breathing, the oxygen level in your blood may drop. This happens if the following conditions occur:

• Your throat muscles and tongue relax more than is normal.
  
• Your tonsils and adenoids are large.
  
• You are overweight. The extra soft tissue in your throat makes it harder to keep the throat area open.
  
• The shape of your head and neck (bony structure) results in somewhat smaller airway size in the mouth and throat area.

With the throat frequently fully or partly blocked during sleep, enough air cannot flow into your lungs, even though your efforts to breathe continue. Your breathing may become hard and noisy and may even stop for short periods of time (apneas).

Central apnea is a rare type of sleep apnea that happens when the area of your brain that controls your breathing doesn’t send the correct signals to the breathing muscles. Then there is no effort to breathe at all for brief periods. Snoring does not typically occur in central apnea.