Obstructive sleep apnoea (also known as OSA) is a condition in which breathing repeatedly stops and starts during sleep. It is the most common form of sleep-disordered breathing in Australia.
Obstructive sleep apnoea happens when the muscles at the back of the throat relax and block the airways during sleep. When this happens, you stop breathing. This can last for up to a minute or even longer, and may happen hundreds of times per night.
The term obstructive sleep apnoea syndrome or obstructive sleep apnoea-hypopnoea syndrome (OSAHS) is often also used when someone has obstructive sleep apnoea plus daytime symptoms, in particular, excessive daytime sleepiness.
Symptoms of obstructive sleep apnoea
The most obvious of the signs and symptoms of obstructive sleep apnoea is snoring. It can be very loud, and sometimes a person’s sleeping partner has to leave the room because of it.
Other symptoms may include:
- Waking up at night with a sensation of choking, coughing or gasping
- Witnessed episodes of apnoea: a sleeping partner sees the person stop and start breathing
- Waking to pass urine one or more times during the night
- Night sweating
- Daytime sleepiness
- Poor concentration or attention span during the day
- Irritability or other mood changes
- Morning headache
- Erectile dysfunction.
People with obstructive sleep apnoea are also more likely to have other medical conditions such as:
- High blood pressure
- Overweight or obesity
- Heart disease (especially heart failure or atrial fibrillation)
- Cerebrovascular disease (conditions that affect the circulation of blood to the brain, e.g. stroke)
- Thyroid disease.
Obstructive sleep apnoea may be associated with lung or airways disease such as chronic obstructive pulmonary disease (COPD) and asthma.
What causes obstructive sleep apnoea?
Obstructive sleep apnoea is caused by the muscles at the back of the throat relaxing too much to allow normal breathing.
After a period ranging from a few seconds to a minute or more, your brain registers that oxygen isn’t being drawn into the body through breathing. The brain then sends out signals to rouse you from sleep, forcing you to take a breath. You may cough or gasp as this happens, then drift back to sleep until it happens again.
This pattern can repeat itself hundreds of times during the night. These cycles interrupt your sleep throughout the night, meaning that you may wake up in the morning feeling tired and unrefreshed.
Who gets obstructive sleep apnoea?
Anyone can develop obstructive sleep apnoea, although it most commonly affects middle-aged, male adults and people who are overweight.
Other factors that increase the risk of obstructive sleep apnoea include:
- Alcohol consumption, especially in the evenings: this can further relax the throat muscles
- Size and shape of the neck, throat and face: for example, having a short, thick neck, a small or receding chin, a narrow throat or a high arched palate
- Having large tonsils
- Chronic (long-term) nasal congestion or obstruction
- Use of sleeping tablets or sedatives
- Family history of obstructive sleep apnoea.
The diagnosis of obstructive sleep apnoea commonly involves an overnight sleep study, known as a polysomnogram. This study can calculate the number of times you stop breathing and also how severe the condition is. It involves placing electrodes on the skin over several parts of your body, including the face and scalp, to record sleep quality, breathing and oxygen levels.
Sleep studies are traditionally performed in special sleep laboratories. There are also some home-based tests that are available, but these are generally not as accurate as those done in special laboratories. Therefore, if a doctor suspects that you have obstructive sleep apnoea they will often refer you for a sleep study at a sleep laboratory and refer you to a sleep specialist.
Obstructive sleep apnoea can lead to serious complications. Excessive daytime sleepiness increases the risk of car accidents, especially single car accidents (those just involving your car) at night.
Obstructive sleep apnoea is also associated with high blood pressure during pregnancy (known as pre-eclampsia) and a higher rate of death from vascular diseases such as heart disease and stroke.
Because the condition is associated with potentially serious issues while driving, people with severe obstructive sleep apnoea should not drive or operate machinery until treatment is seen to be working.
Many people may not be aware of their breathing disturbances at night or the severity of their daytime sleepiness, so it can be helpful to ask a partner about these symptoms.
Treatment depends on the severity of the sleep apnoea. People who are affected only mildly (meaning they don’t have any daytime sleepiness, problems with normal daily activities, high blood pressure or other heart problems) will often respond sufficiently to changes in lifestyle. Such changes include:
- Losing weight
- Avoiding alcohol and drugs that affect sleep
- Spending more time in bed: this gives you a better chance of getting a good amount of sleep
- Using a nasal spray if nasal congestion is a factor
- Changing your sleeping position: sleeping on your side rather than on your back can improve sleep and reduce daytime symptoms. To stop rolling onto your back, it can be helpful to pin a sock containing a tennis ball to the back of your pyjama top, or place pillows or foam blocks behind your back. Alarms are also available that go off if you roll onto your back.
- Raising the head of the bed by 5-8 centimetres may also be helpful.
Continuous positive airway pressure (CPAP)
The most effective treatment for obstructive sleep apnoea is continuous positive airway pressure (CPAP). This treatment involves wearing a close-fitting nasal mask at night. Air is pumped through the mask at low pressure to keep your upper airway open.
CPAP should be considered for anyone who has:
- Severe obstructive sleep apnoea
- Mild to moderate obstructive sleep apnoea with daytime symptoms (sleepiness, problems concentrating or difficulties with other daily activities)
- Mild to moderate obstructive sleep apnoea with high blood pressure or other vascular disease.
Experts recommend that anyone starting CPAP treatment should do so in a specialist clinic to begin with.
People using CPAP should also make lifestyle changes to reduce weight, and avoid alcohol consumption and the use of medicines that affect sleep.
What other treatments are available?
Other options for obstructive sleep apnoea may include:
- Dental appliances or splints: These are individually made splints that are worn during sleep. They may help to push the lower jaw forward and open up the space in the throat. They are usually only effective for mild to moderate obstructive sleep apnoea.
- Surgery: May help people who have blockages in the throat or nose, or when there is an abnormality in the jaw or face bones. Surgery to remove tonsils or adenoids may also be useful if they are causing a problem.
Can obstructive sleep apnoea be prevented?
You may be able to reduce your risk of obstructive sleep apnoea by:
- Sleeping on your side, not on your back: many people only have symptoms when they sleep on their backs, so avoiding this position may be helpful.
- Losing weight if you are overweight or obese
- Not smoking
- Reducing or avoiding alcohol consumption, especially in the evenings
- Avoiding the use of sleeping tablets and other types of sedatives
- Trying to avoid sleep deprivation: give yourself every opportunity to get a good night’s sleep by spending enough time in bed each night.