Snoring is caused by a narrowed airway during sleep. This can be due to large tonsils, a long soft palate or uvula, or, in people who are overweight, excessive flabby tissue in the throat. All these areas relax during sleep.

As well, nasal congestion from allergies or deformities of the cartilage between the two sides of the nose, or other internal nasal obstructions, can contribute to narrowing the airway.

However, the most common cause of a narrowed airway is a tongue muscle that relaxes too much during sleep, and gets sucked back into the throat with each breath taken (refer MRI images).

Snoring occurs because air travels faster through a narrow tube than through a broad one. This rapidly-moving air causes the relaxed soft tissues of the throat (tonsils, soft palate, uvula or excessive flabby tissue) to vibrate. It is this vibration which is the sound of snoring.

By keeping the airway open, air travels more slowly, reducing throat vibrations, and thus reducing or stopping snoring. One of the most effective ways of keeping the airway open during sleep is by holding the tongue forward.