Sleep Apnea Home > Sleep Apnea Cause

In many cases, a blocked throat is to blame for sleep apnea. Another cause of sleep apnea involves faulty signals being sent from the brain to the muscles that control breathing. Medical conditions such as hypothyroidism can also result in sleep apnea.

What Causes Sleep Apnea?

The most common type of sleep apnea is obstructive sleep apnea, caused by relaxation of soft tissue in the back of the throat that blocks the passage of air. Central sleep apnea (CSA) is caused by irregularities in the brain's normal signals to breathe. Most people with sleep apnea will have a combination of both types.

Obstructive Sleep Apnea

Sleep apnea happens when not enough air moves into your lungs while you are sleeping.
When you are awake (and normally when you are asleep), your throat muscles keep your throat open, and air flows into your lungs. However, in obstructive sleep apnea, the throat briefly collapses, causing pauses in your breathing. This happens when:
  • Your throat muscles and tongue relax more than 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 a somewhat smaller airway size in the mouth and throat area.
When the throat is fully or partly blocked during sleep, not enough air flows into your lungs, despite continuing efforts to breathe. Your breathing may become hard and noisy and may even stop for short periods of time (apneas).
With pauses in breathing, the level of oxygen in your blood may drop.

Central Sleep Apnea

Central apnea is a type of sleep apnea that happens when the area of your brain that controls your breathing doesn't send the correct signals to the muscles involved with breathing. There is then no effort to breathe at all for brief periods. Snoring does not typically occur in central sleep apnea.
Written by/reviewed by:
Last reviewed by: Arthur Schoenstadt, MD
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