Sleep apnoea occurs when the walls of the throat come together during sleep, blocking off the upper airway at the level of the tongue. Breathing stops for a period of time (generally between a few seconds and up to one minute) until the brain registers the lack of breathing or a drop in oxygen levels and sends a small wake-up call. The sleeper rouses slightly, opens the upper airway, typically snorts and gasps, then drifts back to sleep almost immediately.
In most cases, the person suffering from sleep apnoea doesn’t even realise they are waking up. This pattern can repeat itself hundreds of times over every night, causing fragmented sleep. This leaves the person with unrefreshed sleep, excessive daytime sleepiness and fatigue. It’s estimated that about five per cent of Australians suffer from this sleep disorder, with around one in four men over the age of 30 years affected.
Degrees of severity
The full name for this condition is obstructive sleep apnoea. Another rare form of breathing disturbance during sleep is called central sleep apnoea. It is caused by a disruption to the nerve messages sent between the brain and the body. The severity of sleep apnoea depends on how often the breathing is interrupted. As a guide:
- Normal – less than five interruptions an hour
- Mild sleep apnoea – between 5 and 15 interruptions an hour
- Moderate sleep apnoea – between 15 and 30 interruptions an hour
- Severe sleep apnoea – over 30 interruptions an hour.
Symptoms
People with significant sleep apnoea have an increased risk of motor vehicle accidents and hypertension and may have an increased risk of heart attack and stroke. In the over-30 years age group, the disorder is about three times more common in men than women. Some of the associated symptoms include:
- Daytime sleepiness, fatigue and tiredness
- Poor concentration
- Irritability and mood changes
- Impotence and reduced sex drive.
Causes
Obesity is one of the most common causes of sleep apnoea. A loss of around 5kg to 10kg may be enough to dramatically reduce the severity of the disorder. Other contributing factors include:
- Alcohol, especially in the evening – this relaxes the throat muscles and hampers the brain’s reaction to sleep disordered breathing
- Certain illnesses, like reduced thyroid hormone or the presence of a very large goitre
- Large tonsils, for instance due to too much growth hormone or a congenital abnormality
- Medications, such as sleeping tablets and sedatives
- Nasal congestion and obstruction.
Treatment
Treatment for sleep apnoea relies on changes to lifestyle, including losing weight and cutting down on alcohol. Any contributing medical condition, such as low production of thyroid hormone, also needs to be corrected. Any surgical conditions such as large tonsils should be corrected.
The most effective treatment available is a mask worn at night that keeps the back of the throat open by forcing air through the nose. This is called ‘nasal continuous positive airway pressure’ (CPAP). However, some people with sleep apnoea find the mask difficult to tolerate.
Another treatment is the use of a mouthguard (or oral appliance or mandibular advancement device). When properly made, it is effective for mild to moderate sleep apnoea. Mouthguards are also used in severe sleep apnoea if the person cannot tolerate the CPAP mask. They work by holding the jaw forward during sleep.
Where to get help
- Your doctor
- Sleep disorders clinic
Things to remember
- Sleep apnoea occurs when the walls of the throat come together during sleep, blocking off the airway above the voice box.
- Around one in four men over the age of 30 years have some degree of sleep apnoea.
- Conservative treatment includes weight loss and cutting back on alcohol.
- Active treatment includes nasal CPAP, mouthguards or surgical correction of upper airway obstruction.
- Daytime sleepiness may distinguish simple snorers from people with sleep apnoea.
You might also be interested in:
Fatigue explained.
Hypersomnia.
Sleep - common disorders.
Sleep deprivation.
Sleep hygiene.
Sleep problems - insomnia.
Snoring.
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