Sleep apnoea can stop a person breathing for longer than a minute at a time repeatedly through the night.
Snoring is typically associated with overweight middle-aged men, but it is more complex and widespread than that, says sleep expert Danny Eckert, who cited the death of Hollywood actor Carrie Fisher of Star Wars fame from sleep apnoea and other causes.
"As we have just seen with Carrie Fisher, the throat area is closing over and over again," says associate professor Eckert, from the research institute Neuroscience Research Australia (NeuRA), who has identified a range of new reasons why some people suffer from sleep apnoea.
"You are still trying to breathe, but the muscles around the throat aren't working in the way they should to keep the airway open. So there are pauses in breathing, lasting 10 seconds or more. And oxygen levels go right down and this places a lot of strain on the heart and the cardiovascular system."
The standard treatment for obstructive sleep apnoea doesn't work for about 50 per cent of people, reveals a new review of current treatments by Professor Eckert and Dr Jayne Carberry in the medical journal Chest.
Constructive sleep apnoea is associated with repeated closing of the throat area from back of the nose to past the tongue over and over again – as often as 100 times an hour in severe cases.
But research has identified other causes, including:
A weakness in throat muscles, which can't keep the airways open at night. Researchers are now looking at how to strengthen these muscles.
Light sleeping and insomnia, which affects about 40 per cent of people with sleep apnoea.
Increased sensitivity to changes in carbon dioxide during the night, which can wake people up. They also argue that more needs to be done for the 50 per cent of the population who can't tolerate positive airway pressure (CPAP) therapy as tolerance and compliance are unacceptably low.
Many find the machine uncomfortable. And going to bed wearing a mask with tubes is not a sexy look.
Oral appliances have varied success and require repeat and often expensive visits to dentists, said the paper.
Weight loss has consistently been shown to reduce the severity of sleep apnoea but losing weight is difficult to do and even harder to keep off, said the paper.
When children breathe through their mouths during the day chances are that they also breathe through their mouths at night. Mouth breathing at night is directly connected to altered levels of carbon dioxide and oxygen in the blood stream. When less oxygen is able to reach the brain, learning and the ability to focus at school becomes a problem for many children.