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 shouldn't drive 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

Obstructive sleep apnoea (OSA) can usually be diagnosed after you've been observed sleeping at a sleep clinic, or by using a testing device worn overnight at home.

If you think you have OSA, it's important to visit your GP in case you need to be referred to a sleep specialist for further tests and treatment.

Before seeing your GP it may be helpful to ask a partner, friend or relative to observe you while you're asleep, if possible. If you have OSA, they may be able to spot episodes of breathlessness.

It may also help to fill out an Epworth Sleepiness Scale questionnaire. This asks how likely you'll be to doze off in a number of different situations, such as watching TV or sitting in a meeting. 

The final score will help your doctor determine whether you may have a sleep disorder.

For example, a score of 16-24 means you're excessively sleepy and should consider seeking medical attention. A score of eight to nine is considered average during the daytime.

An online version of the Epworth Sleepiness Scale can be found on the British Lung Foundation website.

Seeing your GP

When you see your GP, they'll usually ask a number of questions about your symptoms, such as whether you regularly fall asleep during the day against your will.

Your blood pressure will be measured and a blood sample probably sent off to help rule out other conditions that could explain your tiredness, such as an underactive thyroid gland (hypothyroidism).

The next step is to observe you while you're asleep at a local sleep centre. Your GP can refer you to specialist clinics or hospital departments that help treat people with sleep disorders.

The Sleep Apnoea Trust Association has a list of NHS sleep clinics in Scotland.

Observing your sleep

The sleep specialists at the sleep centre may ask you about your symptoms and medical history, and carry out a physical examination.

This may include measuring your height and weight to work out your body mass index (BMI), as well as measuring your neck circumference. This is because being overweight and having a large neck can increase your risk of OSA.

The sleep specialists will then arrange for your sleep to be assessed overnight, either by spending the night at the clinic or taking some monitoring equipment home with you and bringing it back the next day for them to analyse.

Testing at home

In many cases the sleep centre will teach you how to use portable recording equipment while you sleep at home.

The equipment you are given may include:

• a breathing sensor
• sensors to monitor your heart rate
• bands that are placed around your chest
• oxygen sensors that are put on your finger

The equipment records oxygen levels, breathing movements, heart rate and snoring through the night.

If more information about sleep quality is required, a more detailed investigation called polysomnography will be required, which will be carried out at the sleep centre.

Testing at a sleep centre

The main test carried out to analyse your sleep at a sleep centre is known as polysomnography.

During the night, several different parts of your body will be carefully monitored while you sleep.

Bands and small metallic discs called electrodes are placed on the surface of your skin and different parts of your body. Sensors are also placed on your legs and an oxygen sensor will be attached to your finger.

A number of different tests will be carried out during polysomnography, including:

• electroencephalography (EEG) – this monitors brain waves
• electromyography (EMG) – this monitors muscle tone
• recordings of movements in your chest and abdomen
• recordings of airflow through your mouth and nose
• pulse oximetry – this measures your heart rate and blood oxygen levels
• electrocardiography (ECG) – this monitors your heart

Sound recording and video equipment may also be used.

If OSA is diagnosed during the early part of the night, you may be given continuous positive airway pressure (CPAP) treatment. CPAP involves using a mask that delivers constant compressed air to the airway and stops it closing, which prevents OSA.

Read about treating OSA for more information about CPAP.

Once the tests have been completed, staff at the sleep centre should have a good idea about whether or not you have OSA. If you do, they can determine how much it is interrupting your sleep and recommend appropriate treatment.

Determining the severity of OSA

The severity of OSA is determined by how often your breathing is affected over the course of an hour. These episodes are measured using the apnoea-hypopnoea index (AHI).

Severity is measured using the following criteria:

• mild – an AHI reading of 5 to 14 episodes an hour
• moderate – an AHI reading of 15 to 30 episodes an hour
• severe – an AHI reading of more than 30 episodes an hour

Current evidence suggests treatment is most likely to be beneficial in people with moderate or severe OSA. However, some research has suggested treatment may also help some people with mild OSA.

Treatment for obstructive sleep apnoea (OSA) may include making lifestyle changes and using breathing apparatus while you sleep.

OSA is a long-term condition and many cases require lifelong treatment.

Lifestyle changes

In most cases of OSA you'll be advised to make healthy lifestyle changes, such as:

• losing weight if you're overweight or obese
• stopping smoking if you smoke
• limiting your alcohol consumption, particularly before going to bed – the NHS recommends not regularly drinking more than 14 units of alcohol a week; if you drink as much as 14 units a week, it's best to spread this evenly over three or more days
• avoiding sedative medications and sleeping tablets

Losing weight, reducing the amount of alcohol you drink and avoiding sedatives have all been shown to help improve the symptoms of OSA. 

Although it's less clear whether stopping smoking can improve the condition, you'll probably be advised to stop for general health reasons.

Sleeping on your side, rather than on your back, may also help relieve the symptoms of OSA.

Continuous positive airway pressure (CPAP)

As well as the lifestyle changes mentioned above, people with moderate to severe OSA usually need to use a continuous positive airway pressure (CPAP) device.

This is a small pump that delivers a continuous supply of compressed air through a mask that either covers your nose or your nose and mouth. The compressed air prevents your throat closing.

CPAP can feel peculiar to start with and you may be tempted to stop using it. But people who persevere usually soon get used to it and their symptoms improve significantly.

CPAP is available on the NHS and is the most effective therapy for treating severe cases of OSA.

As well as reducing symptoms such as snoring and tiredness, it can also reduce the risk of complications of OSA, such as high blood pressure.

Possible side effects of using a CPAP device can include:

• mask discomfort
• nasal congestion, runny nose or irritation
• difficulty breathing through your nose
• headaches and ear pain
• stomach pain and flatulence (wind)

Earlier versions of CPAP also often caused problems such as nasal dryness and a sore throat. However, modern versions tend to include humidifiers, a device that increases moisture, which helps reduce these side effects.

If CPAP causes you discomfort, inform your treatment staff as the device can be modified to make it more comfortable. For example, you can try using a CPAP machine that starts with a low air pressure and gradually builds up to a higher air pressure as you fall asleep.

Mandibular advancement device (MAD)

A mandibular advancement device (MAD) is a dental appliance, similar to a gum shield, sometimes used to treat mild OSA. 

They're not generally recommended for more severe OSA, although they may be an option if you're unable to tolerate using a CPAP device.

An MAD is worn over your teeth when you're asleep. It's designed to hold your jaw and tongue forward to increase the space at the back of your throat and reduce the narrowing of your airway that causes snoring.

Off-the-shelf MADs are available from specialist websites, but most experts don't recommend them, as poor-fitting MADs can make symptoms worse.

It's recommended you have an MAD made for you by a dentist with training and experience in treating sleep apnoea. MADs aren't always available on the NHS, so you may need to pay for the device privately through a dentist or orthodontist.

An MAD may not be suitable treatment for you if you don't have many – or any – teeth. If you have dental caps, crowns or bridgework, consult your dentist to ensure they won't be stressed or damaged by an MAD.

Surgery for OSA

Surgery to treat OSA isn't routinely recommended because evidence shows it's not as effective as CPAP at controlling the symptoms of the condition. It also carries the risk of more serious complications.

Surgery is usually only considered as a last resort when all other treatment options have failed, and also if the condition is severely affecting your quality of life.

A range of surgical treatments have been used to treat OSA. These include:

• tonsillectomy – where the tonsils are removed if they're enlarged and blocking your airway when you sleep
• adenoidectomy – where the adenoids, small lumps of tissue at the back of the throat above the tonsils, are removed if they're enlarged and are blocking the airway during sleep
• tracheostomy – where a tube is inserted directly into your neck to allow you to breathe freely, even if the airways in your upper throat are blocked
• weight loss (bariatric) surgery – where the size of the stomach is reduced if you're severely obese and this is making your sleep apnoea worse

Surgery to remove excess tissue in the throat to widen your airway (uvulopalatopharyngoplasty) used to be a common surgical treatment for OSA, but it's performed less often nowadays.

This is because more effective treatments are available, such as CPAP. This type of surgery can mean you're unable to use a CPAP device properly in the future if you need to.

Soft palate implants

Soft palate implants make the soft palate, part of the roof of the mouth, stiffer and less likely to vibrate and cause an obstruction. The implants are inserted into the soft palate under local anaesthetic.

The National Institute for Health and Care Excellence (NICE) has said soft palate implants are safe, but they're not currently recommended for treating OSA as there's a lack of evidence about their effectiveness.

However, this form of treatment is recommended for treating snoring associated with OSA in exceptional cases.

Support groups

OSA can have a significant impact on the quality of life for someone with the condition, as well as their friends and families.

As well as causing physical problems such as tiredness and headaches, the condition can have a significant emotional impact and affect your relationships with others.

For support and advice about living with OSA, you may find it helpful to contact a support group, such as:

• British Lung Foundation
• Sleep Apnoea Trust