When you have OSA, you briefly but repeatedly stop breathing while you sleep. Depending on the severity of your apnea, you can stop breathing 5 to 30 times or more every hour.
The problem occurs when your tongue and tissues in your throat relax and move toward the airway in your throat. If the tissues partially cover the airway, they vibrate and cause snoring. When the tissues completely cover the airway, you stop breathing.
As soon as you stop breathing, oxygen levels drop, and your brain nudges you to start breathing again. In most cases, you don’t fully awaken, so you don’t know you stopped breathing.