Causes of Sleep Apnea
Because there are different types of sleep apnea, the causes of the condition are not always the same. Obstructive sleep apnea occurs when the throat muscles and tongue relax during sleep and block the throat. Central sleep apnea is due to faulty communication signals between the brain and the muscles involved with breathing. Other medical conditions, such as hypothyroidism, acromegaly, and Marfan syndrome, are also possible causes of the condition.
The most common type of sleep apnea is obstructive sleep apnea (OSA). It is caused by relaxation of soft tissue in the back of the throat, and this 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.
Intermittent (coming and going) blockage in some part of the upper airways, often due to the throat muscles and tongue relaxing during sleep, can result in sleep apnea. When the muscles of the soft palate at the base of the tongue and the uvula (the small fleshy tissue hanging from the center of the back of the throat) relax and sag, the airway becomes blocked.
When your throat is 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 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 people with central apnea.