What is obstructive sleep apnoea?
Obstructive sleep apnoea (OSA) is a condition where your breathing stops for short spells when you are asleep. The word apnoea means 'without breath', that is, the breathing stops. In the case of OSA, the breathing stops because of an obstruction to the flow of air down your airway. The obstruction to the airflow occurs in the throat at the top of the airway.
What happens in people with obstructive sleep apnoea?
When we sleep the throat muscles relax and become floppy (like other muscles). In most people, this does not affect breathing. If you have OSA, the throat muscles become so relaxed and floppy during sleep that they cause a narrowing or even a complete blockage of the airway.
When the airway is narrowed and the airflow is restricted, at first this causes snoring. If there is a complete blockage then the breathing actually stops (apnoea). The blood oxygen level then goes down which is detected by the brain. Your brain then tells you to wake up and you make an extra effort to breathe, and you start to breathe again with a few deep breaths. You will then normally quickly go back off to sleep again and not even be aware that you have woken up.
If someone watches you, he or she will notice that you stop breathing for a short time, and then make a loud snore and a snort, perhaps even sound as if you are briefly choking, briefly wake up, and then get straight back off to sleep.
It is quite common for many of us to have the odd episode of apnoea when we are asleep, often finishing with a 'snort'. This is of no concern. In fact, some people when they sleep have periods of 10-20 seconds when they do not breathe. However, people with OSA have many such episodes during the night. In fact, the episodes of apnoea are usually only considered 'significant' if they occur more than 10 times per hour, and for each spell of apnoea (stopped breathing) to last 10 seconds or more. People with OSA can have hundreds of episodes of apnoea each night.
So, if you have OSA, you wake up many times during the night. You will not remember most of the times but your sleep will have been greatly disturbed. As a consequence, you will usually feel sleepy during the day. Daytime sleepiness in someone who is a loud snorer at night is the classic hallmark of someone who has OSA.
Who gets obstructive sleep apnoea?
OSA can occur at any age, including children. However, it most commonly develops in middle aged men who are overweight or obese. It is thought that as many as 2 in 100 middle aged men and 1 in 100 middle aged women develop OSA.
Factors that increase the risk of developing OSA, or can make it worse, include the following. They all increase the tendency of the narrowing in the throat at night to be worse than normal.
- Overweight and obesity. Particularly if you have a thick neck as the extra fat in the neck can squash the airway.
- Drinking alcohol in the evening. Alcohol relaxes muscles more than usual and makes the brain less responsive an apnoea episode. This may lead to more severe apnoea episodes in people who may otherwise have mild OSA.
- Enlarged tonsils.
- Taking sedative drugs.
- Sleeping on your back rather than on your side.
What are the symptoms of obstructive sleep apnoea?
People with OSA may not be aware that they have this problem as they do not usually remember the waking times at night. It is often a sleeping partner or a parent of a child with OSA that is concerned about the loud snoring and the recurring episodes of apnoea that they notice. One or more of the following also commonly occur.
- Daytime sleepiness. This is often different to just being 'tired'. People with severe OSA may fall asleep during the day with serious consequences. For example, when driving, especially on long monotonous journeys such as on a motorway. A particular concern is the increased frequency of car crashes involving drivers with OSA. Drivers with OSA have a 2-12 increase risk of having a car crash compared to average.
- Poor concentration and mental functioning during the day.
- Morning headaches.
- Being irritable during the day.
People with untreated OSA also have an increased risk of developing high blood pressure, heart attack, heart failure, and stroke.
Epworth Sleepiness Scale
If you have daytime tiredness, sometimes a questionnaire is used to measure the Epworth Sleepiness Scale. This helps to gauge the level of sleepiness that you feel during the daytime. A high score indicates that you may have a sleeping disorder such as OSA. See separate leaflet called Epworth Sleepiness Scale for details.
How is OSA diagnosed?
If you have symptoms that suggest OSA, or a high score on the Epworth Sleepiness Scale, your GP may refer you to a specialist for tests. There are various types of test that can be done whilst you sleep. The ones done may be determined by local policies and availability of equipment. For example:
- Airflow may be measured whilst you sleep by using a probe placed under your nose.
- Sensors may be used to record snoring volume and body movement whilst you sleep.
- The oxygen level in your blood can be monitored by a probe clipped onto your finger.
- Breathing can be monitored and recorded by the use of special belts placed around the chest and abdomen.
- A video of you sleeping may be helpful.
You may be asked to spend a night in hospital for the tests to be done. However, some of the tests may be done in your own home from equipment supplied by the specialist. The information gained from the tests can help a specialist to firmly diagnose or rule out OSA.
OSA and driving
If you are diagnosed with OSA and you are a driver, you must not drive and you must inform the DVLA (Driver and Vehicle Licensing Agency). For normal car drivers, you will usually be allowed to resume driving after you no longer have daytime sleepiness with treatment. However, special rules apply if you have an HGV or similar license.
What is the treatment for OSA?
Things that can make a big difference include:
- Losing some weight if you are overweight or obese.
- Not drinking alcohol for 4-6 hours before going to bed.
- Sleeping on your side or in a semi-propped position.
Mandibular advancement devices
The mandible is the lower jaw. There are devices that you can wear inside your mouth when you sleep. They work by pulling the mandible forward a little, which means the throat may not narrow as much in the night. These devices look a bit like gum shields that sports-people wear. Although you can buy these devices without a prescription, it is best to get one properly fitted by a dentist if one is recommended. These devices can work well in some cases.
Continuous positive airway pressure (CPAP)
This is the most effective treatment and is used if other treatments are not successful. This treatment involves wearing a mask when you sleep. A quiet electrical pump is connected to the mask to pump room air into your nose at a slight pressure. The slightly increased air pressure keeps the throat open when you are breathing at night and so prevents the blockage of airflow. The improvement with this treatment is often very good, if not dramatic.
If CPAP works, (as it does in most cases) then there is an immediate improvement in sleep. Also, there is an improvement in daytime wellbeing as daytime sleepiness is abolished the next day. Snoring is also reduced or stopped. The device may be cumbersome to wear at night, but the benefits are usually well worth it. Comments like "I haven't slept as well for years" have been reported from some people after starting treatment with CPAP.
Surgery is not often useful. However, sometimes an operation may be helpful to increase the airflow into your airway. For example, if you have large tonsils or adenoids, it may help if these are removed. This is more commonly done in children with OSA. If you have any nasal blockages, an operation may help to clear the blockage.