Sleep apnoea is a common disorder. However, because its symptoms occur while you sleep, it can be easily overlooked, or mistaken for straight-up tiredness. So how do you know if you have it?
We talk to sleep physician Dr Kirk Kee from the Royal Melbourne Hospital and Baker Specialist Clinics to learn why sleep apnoea needs to be on your health knowledge radar, how the condition differs between men and women and how it's linked to chronic diseases.
There are several types of sleep apnoea, but the most common type is called obstructive sleep apnoea (also known as OSA).
When you sleep, the muscles in your body relax or even become paralysed, to ensure you don't move around when you are asleep. This is a good thing – except when it's your airway muscles.
"In obstructive sleep apnoea, your upper airway – the area behind your mouth – narrows or even completely blocks off because the muscles holding it open relax and become floppy," says Dr Kee.
The narrowing or blocking of your airways – which can happen up to several hundred times a night – causes some follow-on effects.
Firstly, you are unable to breathe, your oxygen levels fall, which creates a stress response in the body. Your heart rate and blood pressure rise and you release the hormone adrenaline.
"Your body thinks it is being suffocated," says Dr Kee.
"Eventually your brain partially 'wakes you up', which activates the muscles in your throat and tongue and opens up your airway again. You then fall back asleep.
"But this can happen over and over throughout the night."
This is the tricky part. Not only do the main symptoms of OSA occur while you're asleep and unaware, the signs and symptoms, especially in women, can be subtle.
Turn to the medical textbooks and you'll find the typical sleep apnoea patient described as an overweight, middle-aged male who snores loudly and falls asleep a lot during the day.
"This is not surprising because the original descriptions were all taken from studies of men," says Dr Kee.
Unfortunately, this has meant that the condition may be overlooked or missed in women.
"Women can of course present in the same way men do, however we find this is less common," says Dr Kee. "What we are increasingly learning from studies looking specifically at women is that [typical male presentation] is not how many women with sleep apnoea present.
"Instead, women will describe a tiredness, fatigue or a lack of energy. Often they will say they don't have time to nap. They might also describe a lowered mood or headaches or perhaps waking up frequently overnight."
Being so broad in nature, these symptoms can be misinterpreted at the doctor's office and women are instead often treated for other conditions such as insomnia or depression. Sleep apnoea might not even be considered.
"While men are twice as likely to have sleep apnoea than women, they are eight times more likely to be diagnosed with it – suggesting that many women with sleep apnoea are being missed," says Dr Kee.
Other signs of possible sleep apnoea include:
Research reveals that menopause greatly increases the risk of sleep apnoea. But why is this the case?
"[The hormones] oestrogens and progesterone help make the muscles in your upper airway stay open during sleep," says Dr Kee. "In menopause, the levels of these hormones reduce and the percentage of women with sleep apnoea gradually increases."
Large research studies suggest that having severe sleep apnoea results in increased rates of heart disease and dementia in both men and women.
As Dr Kee explains, these types of studies are called 'epidemiological studies', whereby researchers study a group of people with a disease (in this case, sleep apnoea) and compare them to people without the disease.
"When they have done studies like these, they have been able to show that patients with sleep apnoea are more likely to have heart attacks or strokes, be diagnosed with cognitive impairment (dementia), or develop other diseases like diabetes, high blood pressure or depression," says Dr Kee.
"Other studies have shown that people with sleep apnoea are more likely to have car accidents or miss days at work."
If you suspect you might have sleep apnoea, but don't have a bed partner – or someone who will notice you snoring or stopping breathing – then you could consider recording a night of sleep to pick up on these clues.
"There are lots of apps for your smartphone which will do that," says Dr Kee.
However, if you have significant symptoms then Dr Kee doesn't recommend relying on a recording, or a partner's eyewitness account. "I have seen many patients who were 100% certain they didn't snore or stop breathing, who actually had very severe sleep apnoea," he says.
If you suspect you have sleep apnoea, or you have any related symptoms – even if you aren't sure you snore – Dr Kee says a discussion with your doctor for a referral for further investigation is a good idea.
"This is especially the case if other diagnoses and treatments have been tried and been unsuccessful," he says.
For those with significant symptoms, Dr Kee suggests talking to your doctor about seeing a sleep specialist.
"Some doctors might suggest going directly for a sleep study without seeing a specialist and in some cases, this might be appropriate," he says.
"However, it is important to remember that if your sleep study test is 'normal' it doesn't mean your symptoms are. Significant symptoms should prompt referral to a specialist."
"Even if sleep apnoea is not the cause [of your symptoms], being seen by a sleep specialist might reveal an alternative diagnosis such as restless leg syndrome, circadian rhythm disorder or other issues with your sleep."
"We aren't meant to go through life exhausted or sleeping poorly, so if you have concerns, talk to your doctor!"
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