Snoring occurs when the flow of air from the mouth or nose to your lungs makes the tissues of the airway vibrate. This usually is caused by a blockage (obstruction) or narrowing in the nose, mouth, or throat (airway).
When you inhale during sleep, air enters the mouth or nose and passes across the soft palate (the back of the roof of the mouth) on its way to the lungs. The back of the mouth-where the tongue and upper throat meet the soft palate and uvula-is collapsible. If this area collapses, the airway becomes narrow or blocked. The narrowed or blocked passage disturbs the airflow, which causes the soft palate and uvula to vibrate and knock against the back of the throat, causing snoring. The tonsils and adenoids may also vibrate. The narrower the airway is, the more the tissue vibrates, and the louder the snoring is.
You do not snore when you are awake because the muscles of the throat hold the tissues in the back of the mouth in place. When you sleep, the muscles relax, allowing the tissues to collapse.
Snoring can be so loud that it keeps your bed partner awake. You may also have a less restful sleep. Sleep quality may decrease as the loudness of the snoring increases. And snoring can result in daytime sleepiness.