Snoring can be the stuffed nose kind of snoring or the back of the mouth/throat, really noisy kind of snoring. While it is important to note that any kind of snoring that disrupts sleep should not be ignored, the type of snoring that is caused by congestion from colds, allergies or nasal irritations, is generally intermittent and stops once the cold or irritation is cleared.
More persistent snoring gets louder over a period of time and comes from a change in physical structure. It happens because as air passages narrow, pressure increases and the vibration and noise follow.
The primary causes of narrowing of the air passage are:
1) Larger soft tissue size - the tongue and soft palate gain weight with the rest of the body and larger soft tissue crowds the airway.
2) Increased relaxation of the soft tissues - a natural occurrence in aging, soft tissues relax into the airway when a snorer sleeps on his/her back.