Obstructive sleep apnoea

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.

Apnoea and hypopnoea

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

People with OSA may experience repeated episodes of apnoea and hypopnoea throughout the night. These events may occur around once every one or two minutes in severe cases.

As many people with OSA experience episodes of both apnoea and hypopnoea, doctors sometimes refer to the condition as obstructive sleep apnoea-hypopnoea syndrome, or OSAHS.

The term "obstructive" distinguishes OSA from rarer forms of sleep apnoea, such as central sleep apnoea, which is caused by the brain not sending signals to the breathing muscles during sleep.

Symptoms of OSA

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.

During an episode, the lack of oxygen triggers your brain to pull you out of deep sleep – either to a lighter sleep or to wakefulness – so your airway reopens and you can breathe normally.

These repeated sleep interruptions can make you feel very tired during the day. You'll usually have no memory of your interrupted breathing, so you may be unaware you have a problem.

When to seek medical advice

See your GP if you think you might have OSA.

They can check for other possible reasons for your symptoms and can arrange for an assessment of your sleep to be carried out through a local sleep centre.

As someone with OSA may not notice they have the condition, it often goes undiagnosed.

Read more about diagnosing OSA.

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

Treating OSA

OSA is a treatable condition, and there are a variety of treatment options that can reduce the symptoms.

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.

However, for most people surgery isn't appropriate and may only be considered as a last resort if other treatments haven't helped.

Read more about treating OSA.

Complications of OSA

The treatments mentioned above can often help control the symptoms of OSA, although treatment will need to be lifelong in most cases.

If OSA is left untreated, it can have a significant impact on your quality of life, causing problems such as poor performance at work and school, and placing a strain on your relationships with others.

Poorly controlled OSA may also increase your risk of:

• developing high blood pressure (hypertension)
• having a stroke or heart attack
• developing an irregular heartbeat – such as atrial fibrillation
• developing type 2 diabetes – although it's unclear if this is the result of an underlying cause, such as obesity

Research has shown someone who has been deprived of sleep because of OSA may be up to 12 times more likely to be involved in a car accident.

If you're diagnosed with OSA, it may mean your ability to drive is affected. It's your legal obligation to inform the Driver and Vehicle Licensing Agency (DVLA) about a medical condition that could have an impact on your driving ability.

Once a diagnosis of OSA has been made, you may be advised to stop driving until your symptoms are well controlled.

The GOV.UK website has advice about how to tell the DVLA about a medical condition.

Preventing OSA

It's not always possible to prevent OSA, but making certain lifestyle changes may reduce your risk of developing the condition.

These include:

• losing weight if you're overweight or obese
• limiting how much alcohol you drink and avoiding alcohol in the evening
• stopping smoking if you smoke
• avoiding the use of sleeping tablets and tranquillisers