What causes snoring?
When we are awake, the muscles of the throat hold the throat open, so that air passes in smoothly as we breathe. During sleep, these muscles relax and the throat sags inwards, causing air turbulence, particularly as we breathe in. Snoring occurs when the roof of the mouth (soft palate and uvula – the uvula is the piece of tissue that dangles at the back of the throat), and sometimes the base of the tongue as well, starts to vibrate intermittently as a result of excessive turbulence. (Interestingly, astronauts hardly ever snore in space, because without the pull of gravity, the throat and tongue will not sag in.)

- have a small jaw and narrow throat and/or a large uvula and base of tongue
- drink alcohol or take sleeping pills, because both of these make the throat muscles very relaxed, and so worsen turbulence in the throat
- are overweight, particularly if you have a fat neck (collar size over 43 cm or 17 inches). This is because more muscle power is needed to hold the throat open if the neck is fat, and so the throat will become more narrow as the muscles relax during sleep
- breathe through your mouth rather than your nose. When you breathe through your mouth the air hits the back of the throat head-on, increasing turbulence, whereas in nose breathing, it enters the throat in parallel with it. This is why any blockage of the nose will cause snoring; we all snore when we have a cold. Some people have a permanent blockage from polyps in the nose or because the wall between the two sides of the nose (nasal septum) is shifted to one side
- smoke, because smoking may cause swelling and inflammation of the lining of the throat
- sleep on your back, because when the muscles are relaxed, the throat is particularly narrow in this position
- eat a large meal before bed, because a full stomach presses upwards on the diaphragm and can lead to laboured breathing
- have relatives who snore as snoring tends to run in families.
- have a round-shaped head rather than a long, thin head. In round-headed people, the tissue has to fall back a shorter distance to narrow the throat (Sleep and Breathing 2001;5:79-91).

Written by: Dr Margaret Stearn
Edited by: Dr Margaret Stearn
Last updated:
Friday, February 26th 2010
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Comments on this article
Posted by Anne on 28/09/2010 at 11:12
I started snoring after having a cold/ chest infection on holiday in 1999. as wll assnorimgi now have great difficulty sleeping at night i.e. waking every hour or so , with a very dry mouth and falling asleep during the day,particularly if it is hot or if i am on abus or train. Any suggestions?
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What causes snoring?
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Fascinating facts
41.5% of the UK population snore (British Snoring and Sleep Apnoea Association)
In the UK, there are about 15 million snorers - 10.4 million males and 4.5 million females (British Snoring and Sleep Apnoea Association)
A study at the University of Erlangen, Germany, found that many young people snore; 61% of medical students (both male and female) have been told so by their partners
Snoring is said to have been useful to primitive man, frightening away predators at night
Churchill and Mussolini were both famous snorers
A doctor at the University of Minnesota, USA, found that the snores of 12% of people referred to his clinic exceeded 55 decibels - the maximum legal outdoor night-time noise in Minnesota. "They could get arrested for disturbing the peace - that's how loud the noise is," he said
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