It is fairly normal for most of us to snore from time to time, especially if we are tired.
The rattling sound we hear in people who snore is actually caused by the tissues in your throat, such as the soft palate and uvula, vibrating.
Some people, however, actually have a minor defect in their throat tissues. The defect prevents the proper amount of air from entering your windpipe. This condition is called sleep apnea. Obstructive sleep apnea is a more serious form of sleep apnea. People with chronic conditions like this often suffer from restless sleep, and can develop more serious conditions, such as high blood pressure, heart arrhythmias, and even congestive heart failure.
Restricted airways in people with sleep apnea are caused by many things, such as an abnormally large uvula (the small finger-like projection hanging in the back of the throat), blocked nasal passages, a poorly developed lower jaw, and in more serious cases, polyps, cysts, or a deviated septum.
Recent research has shown that the brain plays a role in snoring. In addition to physical obstructions in the airway, distorted signals from the brain stem can cause a malfunction in the muscles that control breathing during sleep.