IN BRIEF: Snoring, mainly a male vice, is usually seen as an annoying habit, but did you know that there is also a more sinister side to snoring?

Everyone snores to some extent. The upper airway is a tube lined with muscles, including those of the tongue and soft palate. The upper airway becomes relaxed during sleep, resulting in the airway sagging inwards every time you breathe in. If your mouth is open, this sets up a vibration: the infamous snore.

Heavy snoring may in some cases cause the upper airway to collapse completely, cutting off the airflow. When this happens, the sleeper automatically struggles to regain breath. The rib cage and diaphragm heave, causing abnormal changes in air pressure within the lungs. The flow of blood within the chest, heart and lungs is impaired. Blood pressure rises sharply and levels of oxygen in the blood fall, affecting the heart's function. At this point snoring becomes dangerous, especially to those suffering from heart disease or blood circulation problems. If the snorer is healthy, this state of suffocation lasts for about 10 to 15 seconds, at which point the brain centres that control breathing alert the rest of the brain to the danger and the snorer will begin to wake up.

This condition in which breathing stops temporarily for dozens or even a hundred times a night is called sleep apnoea. Often, apnoea is worsened by excessive weight, having oversized tonsils, or having other structural or neurological (nerve) problems.

Symptoms of sleep apnoea are fatigue and low energy levels during the day, sleepiness and of course, snoring. If you always feel tired, discuss the possibility of sleep apnoea with your doctor - there is growing evidence that it may cause high blood pressure, heart attacks and heart problems, strokes and cognitive (thinking) problems.

Snoring might be more than a disturbance to your sleeping partner, it may be a sign of something quite important to your health.