what causes obstructive sleep apnea?
When you are awake, throat muscles help keep your airway open to allow airflow into your lungs. When you sleep, the muscles that support the soft palate, uvula, tonsils and side walls of the throat and tongue relax, which can narrow or fully block your airway. This may be a result of:
- Throat muscles and tongue relaxing more than normal
- Large tongue and tonsils occluding the opening of your airway
- Excess weight and obesity, which is associated with soft tissue of the mouth and throat causing obstruction of the airway
- The shape of your head and neck (bony structure) which may be causing a smaller airway size in the mouth and throat area causing blockage
- The ageing process limiting your ability to keep your throat muscles stiff during sleep causing narrowing or obstruction of the airway
Not enough air flows into your lungs if your airway is partially or fully blocked during sleep. As a result, loud snoring and a drop in your blood oxygen level can occur. If the oxygen drops to a dangerous level, it triggers your brain to disturb your sleep. This helps tighten the upper airway muscles and open your windpipe. Normal breathing then starts again, often with a loud snort or choking sound.
Frequent drops in your blood oxygen level and reduced sleep quality can trigger the release of stress hormones. These hormones raise your heart rate and increase your risk for high blood pressure, heart attack, stroke, and arrhythmias (irregular heartbeats). The hormones also can raise your risk for, or worsen, heart failure. Untreated sleep apnea also can lead to changes in how your body uses energy. These changes increase your risk for obesity and diabetes.