Sleep Apnoea


Sleep Apnoea is a condition in which breathing stops momentarily during sleep. There are two types of Sleep Apnoea, Obstructive Sleep Apnoea (OSA) and Cental Sleep Apnoea (CSA).

Obstructive Sleep Apnoea.

In normal snoring, the muscles which hold the pharynx (the part of the throat at the back of the of the tongue) open relax during sleep, partially choking the airway and causing the pharyngeal walls to vibrate, giving the sound of snoring.

Obstructive Sleep Apnoea (OSA) occurs when the pharyngeal narrowing results in a complete block of the airway during sleep.

Causes of OSA.

Obstructive Sleep Apnoea can be caused or worsened by several factors including:

Effects of Obstructive Sleep Apnoea.

As the body's oxygen stores can last only a few minutes, when breathing in of fresh air is reduced or stopped for more than a few seconds, the changes in oxygen and carbon dioxide levels stimulate the brain to cause arousal from sleep and to increase respiration.

When the brain wakes up, it allows a return of strength to the pharyngeal muscles, the airway opens and breathing returns to normal. Sleep returns, the airways narrow again and the pattern repeats itself. In severe cases, this cycle can be repeated every 1-2 minutes. When the apnoeas and arousals occur frequently, the night's sleep can become highly disrupted and Excessive Daytime Sleepiness occurs the next day. As arousal rarely results in full wakefulness, few or none of the events can be remembered the next day.


Syptoms of Obstructive Sleep Apnoea may include:


If you suspect that you may have OSA, consult your GP. Your GP may then may refer you to a sleep specialist who may require a sleep study to be done in a sleep laboratory.


Treatment can vary from person to person and according to the severity of the OSA. For mild OSA treatment may include:

For moderate or severe OSA treatment may involve:

Central Sleep Apnoea (CSA)

In the less common Central Sleep Apnoea, hypoventilation (low respiration) is caused by reasons other than an obstructed upper airway.

Causes of Central Sleep Apnoea.

CSA can result from either:

Symptoms of CSA.

As in OSA, Daytime Sleepiness and spouse reported apnoeas are common as well as symptoms resulting from sleep disturbance and low oxygen levels like morning headaches, loss of memory, poor concentration, bedwetting or passing urine at night, depression and breathlessness. Unlike OSA however, there is usually no snoring present. Insomnia or difficulty in sleeping is another common problem.


Diagnosis is as per Obstructive Sleep Apnoea.


Central Sleep Apnoea may be treated in the various ways:

Further Reading


  1. Naughton, M. & Pierce R. Snoring, Sleep Apnoea and Other Sleep Related Problems. Published by the Victorian Tuburculosis and Lung Association: 1996.
  2. Naughton, M. & Pierce R. Sleep Related Breathing Disorders. NODSS Guide to Sleep Disorders: 1999.

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