Snoring arises when breathing is obstructed. This can be caused by a cold or an anatomical irregularity in the nose or throat.
However, the most common cause of snoring is, that the muscles in and around the throat relax too much when we are asleep. This means that the opening in the throat becomes narrow, and air has difficulty in passing. As one requires the same amount of air to the lungs, the air intake speed increases. Pressure in the throat increases, and the uvula and soft palate begin to vibrate. The noise produced by these vibrations is called snoring.
Therefore, snoring is a sign of troubled breathing during sleep. The louder the snoring sound, the narrower the opening in the throat.