Snoring - Causes of snoring

Snoring is caused by the vibration of the soft tissue in your head and neck as you breathe in.

It can affect the:

nasal passages
soft palate – a soft layer of tissue at the back of the roof of the mouth
base of the tongue
tonsils – two small glands above the tongue where the mouth meets the throat
uvula – a small cone-shaped section of tissue that hangs from the soft palate between the tonsils

While you're asleep, the airways in your head and neck relax and narrow. It's thought that the narrowing of the airways increases the speed you breathe out and changes air pressure in your airways. This causes the soft tissue to vibrate by sucking the sides of the airways in.

The same effect can also be the result of partially blocked airways, which may be caused by conditions such as enlarged tonsils and colds.

Evidence suggests that snoring will get worse over time if left untreated. The vibrations that occur during snoring appear to damage blood vessels that supply muscles in the head and neck. Over many years, this causes the muscles to weaken.

If your head and neck muscles are weakened, it will affect their ability to keep your airways open, making you more likely to snore frequently and loudly.

Increased risk

Some things that can increase your risk of habitual snoring include:

obesity – particularly if you have a large amount of fat around your neck; people with a neck circumference of more than 43cm (17 inches) usually snore a lot
drinking alcohol – alcohol relaxes your muscles when you sleep, which increases the narrowing of your airways
sedatives and some types of antidepressants – in some people, these medications can have a similar effect to alcohol on the muscles
smoking – tobacco smoke can cause your airways to become inflamed, which causes greater narrowing of the airways
allergic rhinitis – where the inside of your nose becomes swollen and inflamed as a result of an allergic reaction to substances such as dust or pollen

People with severe snoring may have obstructive sleep apnoea, a condition where the airways become temporarily blocked during sleep.