According to Lynn A. D'Andrea, a sleep specialist at the University of Michigan Medical School, snoring is not an illness, but it is a symptom. Just as a cough can be a symptom of pneumonia, snoring can be a symptom of obstructive sleep apnea. Obstructive sleep apnea is a disorder characterized by snoring, labored breathing and repetitive obstructed pauses or gasps in a person�s breathing during sleep. The obstructed pauses result from complete obstruction or blockage of the airway and may be associated with decreases in oxygen levels. Typically, the obstruction is terminated by an arousal�that is, the snorer briefly wakes up--leading to fragmented, less restful sleep. Obstructive sleep apnea can cause excessive daytime sleepiness, decreased attention and poor concentration, and decreased energy levels. The consequences of these behavioral problems can be quite severe and include motor vehicle accidents if a sufferer becomes inattentive or falls asleep while driving. Obstructive sleep apnea is also causally related to vascular complications such as hypertension. Snoring without evidence of obstructive sleep apnea may be an independent risk factor for hypertension and the daytime behavioral problems mentioned above, but how snoring alone causes problems remains unknown.
The prevalence of snoring and obstructive sleep apnea seems to increase with age, especially after 65 years of age. Additional risk factors associated with the development of snoring include weight gain, alcohol consumption, allergies, nasal obstruction, use of muscle relaxants or sedatives, and smoking.
Source: Scientific America