Obstructive sleep apnoea (OSA) is a relatively common condition where the walls of the throat relax and narrow during sleep, interrupting normal breathing. This may lead to regularly interrupted sleep, which can have a big impact on quality of life and increases the risk of developing certain conditions.
There are two types of breathing interruption characteristic of OSA:
apnoea– where the muscles and soft tissues in the throat relax and collapse sufficiently to cause a total blockage of the airway; it's called an apnoea when the airflow is blocked for 10 seconds or more
hypopnoea– a partial blockage of the airway that results in an airflow reduction of greater than 50% for 10 seconds or more
The symptoms of OSA are often first spotted by a partner, friend or family member who notices problems while you sleep.
Signs of OSA in someone sleeping can include: loud snoring, noisy and laboured breathing, repeated short periods where breathing is interrupted by gasping or snorting.
Some people with OSA may also experience night sweats and may wake up frequently during the night to urinate.
Causes of OSA
It's normal for the muscles and soft tissues in the throat to relax and collapse to some degree while sleeping. For most people this doesn't cause breathing problems.
In people with OSA the airway has narrowed as the result of a number of factors, including:
being overweight – excessive body fat increases the bulk of soft tissue in the neck, which can place a strain on the throat muscles; excess stomach fat can also lead to breathing difficulties, which can make OSA worse
being male – it's not known why OSA is more common in men than in women, but it may be related to different patterns of body fat distribution
being 40 years of age or more – although OSA can occur at any age, it's more common in people who are over 40
having a large neck – men with a collar size greater than around 43cm (17 inches) have an increased risk of developing OSA
taking medicines with a sedative effect – such as sleeping tablets or tranquillisers
having an unusual inner neck structure – such as a narrow airway, large tonsils, adenoids or tongue, or a small lower jaw
alcohol – drinking alcohol, particularly before going to sleep, can make snoring and sleep apnoea worse
smoking – you're more likely to develop sleep apnoea if you smoke
the menopause (in women) – the changes in hormone levels during the menopause may cause the throat muscles to relax more than usual
having a family history of OSA – there may be genes inherited from your parents that can make you more susceptible to OSA
nasal congestion – OSA occurs more often in people with nasal congestion, such as a deviated septum, where the tissue in the nose that divides the two nostrils is bent to one side, or nasal polyps, which may be a result of the airways being narrowed
Treatment options for OSA include:
lifestyle changes – such as losing excess weight, cutting down on alcohol and sleeping on your side
using a continuous positive airway pressure (CPAP) device – these devices prevent your airway closing while you sleep by delivering a continuous supply of compressed air through a mask
wearing a mandibular advancement device (MAD) – this gum shield-like device fits around your teeth, holding your jaw and tongue forward to increase the space at the back of your throat while you sleep
Surgery may also be an option if OSA is thought to be the result of a physical problem that can be corrected surgically, such as an unusual inner neck structure.
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