Snoring and obstructive sleep apnoea (OSA)

What is snoring?

Snoring is noise produced from the soft palate and other parts of the upper respiratory tract. It is most common in men, especially older, middle-aged and obese men.

Apnoea refers to short spells when breathing stops. In obstructive sleep apnoea, the throat is sucked closed during sleep.

Obstructive Sleep Apnoea OSA When we breathe in, the pressure in our throat and chest drops below the outside atmospheric pressure, which is why air goes into our lungs.

The higher pressure in the surrounding atmosphere tries to squeeze our throat closed as we breathe in, but the muscles that open the throat resist this. But when we fall asleep these throat opening muscles relax so that the throat gets narrower each time we inhale.

When throat is narrowed to a slit, the air flow is disturbed so that the audible vibration of snoring is heard. If the throat is so narrow that it is partially or completely blocked, the sleeper will fight for breath until they wake up.

Apnoea often ends with a loud snore or gasp, along with movements of the whole body. This awakening is sufficient to make their throat opening muscles work so they can breathe in again, but they usually fall asleep again so quickly that they don't remember it happening.

In Obstructive Sleep Apnoea OSA, this cycle repeats itself throughout the night as the muscles relax and the throat blocks off again. During sleep, the intervals between the breaths (apnoeic spells) or the reduction of the depth of breathing (hypopnoea) lead to a decrease of the oxygen in the blood and will cause the afflicted person to wake up many times during the night.

Many Obstructive Sleep Apnoea OSA patients wake up before their throat muscles have recovered and are frightened by the sensation of choking, but breathing will always resume after a few seconds.

People with Obstructive Sleep Apnoea OSA also expend more energy than average on breathing during the night. Their quality of sleep therefore decreases and leads to sleepiness during the day. This urge to sleep can be very strong and people have been known to fall asleep during conversations, meals, driving a car and even when surrounded by dangerous machinery or dangerous environment.