Snoring is among the most common sleep problems. While it is neither a delibitating nor death threatening condition, it still causes some grave problems that may or may not directly root from its effects.
Most middle-aged men are the victims and there is high risk towards obese persons. This is true since fleshy necks are most likely to have more muscles that would collapse during relaxed breathing.
Snoring roots from narrowed air passage in between the throat and the nose. When we sleep, this passage narrows due to relaxation of the tissues. This explains why we only snore when we are at our most restful position.
With a narrowed passage, the pressure of the air from the mouth and back are highly increased. Thus, this will drive the flapping muscles to vibrate more, which in turn create the snoring sounds.
Anything that helps narrow the air passage and the muscles to relax will most likely initiate the vibrations. Say, substances that promote muscle relaxation will encourage the tongue to fall back or the throat muscles to be relived from tension.
Stuffy nose can also be considered as a culprit since it limits the space in which air can pass...