As you breathe, air travels through passages in your nose and throat. When these air passages are wide enough to allow air to flow freely, you breathe quietly. However, if the passages become too narrow, the tissues of the throat may start to vibrate, leading to snoring.
Obstruction to normal airflow may occur at multiple levels. Problems in the structure of the nose may obstruct breathing. A crooked, or deviated, septum or swollen turbinates can lead to nasal obstruction. Nasal polyps, allergies, and chronic sinusitis can also cause nasal obstruction. These problems, in turn, can lead to mouth breathing and contribute to snoring.
Large tonsils, a floppy soft palate or an elongated uvula are common findings with snorers. These anatomic abnormalities lead to decreased movement of air through the mouth. A receding jaw or enlarged tongue may also obstruct oral breathing, by allowing the tongue to come into contact with the back of the throat.
Finally, weight gain increases the thickness of the tissues of the neck and throat, compromising the diameter of the airway.
It is common for snorers to have multiple anatomic factors that contribute to their snoring problem, as opposed to just a single factor.