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.)

Schematic picture of the mouth

Snoring is particularly likely to happen if you:

  • 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 throatsleep 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).


How snoring occurs


First published on: embarrassingproblems.com
Reviewed and edited by: Dr Anna Cantlay
Last updated: October 2020

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