The most common factors that cause increased snoring are:
Sleeping on your back. In this position gravity pulls the jaw and tongue down and back. This causes the mouth to open and the tongue to drop back into the airway, and leads to narrowing of the air passage. Sixty percent of all snorers will snore only or most often while sleeping on their back.
Sleeping on your back.Difficulty with nasal breathing. Breathing through the nose is a more efficient way to bring air into the lungs than mouth breathing. A deviated septum, allergies, pregnancy, or a cold can cause the blood vessels in the nasal area to swell, which can lead to congestion or stuffiness in the nose. This can cause mouth breathing and increased resistance in the air passage.
Obesity. In overweight individuals, excess fat deposits in the area of the neck and throat cause an increase in the size of the tissues or increased pressure on the tissues that surround the air passage. This leads to narrowing of the airway. Obesity is a major predisposing factor to snoring.
Enlarged soft tissues in the throat area. Snoring is much more prevalent in people who have a large tongue, long soft palate, large uvula, or large tonsils. When those tissues are enlarged, there can be a decrease in airway space. Enlarged tonsils and adenoids are the primary cause of snoring in children.
A small lower jaw. People who have a receding chin related to a small lower jaw are more likely to snore because there is less room in the back of the throat for the soft tissues and tongue. This reduction in space decreases the size of the air passage and causes increased snoring.
Certain medications and alcohol consumption. Some drugs (particularly certain tranquilizers and antihistamines) and alcohol can cause greater relaxation in the soft tissues and muscles in the throat. This can lead to narrowing of the air passage during sleep, which increases the chance of snoring.
Cigarette smoke and other irritants. These irritants can cause increased nasal congestion and mucous in the throat area, which can lead to increased snoring.