Sleep apnoea is a condition where people repeatedly stop breathing while asleep. People with sleep apnoea often complain of daytime sleepiness, difficulties concentrating, and they tend to have high blood pressure. The people around them usually complain about their nightly snoring, gasping, and choking noises.
About 5% of people have treatable moderate or severe sleep apnoea, which means they stop breathing 15 times or more times per hour while asleep. A larger number of people – as many as 20% of middle-aged folk – have mild sleep apnoea, which means they stop breathing around five to 15 times an hour. Although this may sound pretty scary, it’s still not clear that this mild version causes ill health.
Left untreated, sleep apnoea will not only shorten your life by hastening a string of illnesses, it may also increase your risk of suffering from depression. And the general sleepiness of people with the condition is thought to as much as triple their risk for car accidents and injury.
Stroke risk
The prevalence of sleep apnoea increases in ageing societies that are getting heavier, along with other age and obesity-related diseases. But studies from around the world show your risk of developing these diseases is strongly influenced by whether or not you have sleep apnoea in the first place. In particular, the condition has been linked to stroke and cancer.
The consequences of stroke can range from between temporary inconvenience to serious life-altering disability and death. Smoking, cholesterol, and high blood pressure are three key causes of stroke that you can control. And, unfortunately, sleep apnoea has a big impact on the latter.
The condition causes your daytime blood pressure to increase a little bit over the long term. And, while you’re asleep, it causes massive spikes in blood pressure. Sleep apnoea also might make your ability to process cholesterol a little less efficient.
So it’s not terribly surprising that studies from Spain, the United States, and Australia have all found people with untreated sleep apnoea are three times more likely to have a stroke.
And cancer
One of the more surprising recent research findings is sleep apnoea’s influence on cancer risk. Researchers really weren’t expecting to find this because we’d always thought sleep apnoea mainly influenced heart disease.
But in study after study from around the world we’ve seen that sleep apnoea increases the risk of cancer as well. And this association is not explained by other known cancer risks.
At this stage, we don’t think sleep apnoea causes cells to become cancerous. It might be that if you have a few cancer cells in your body, the constant up and down of oxygen levels in your blood while you sleep causes those cells to grow more quickly. So instead of having a cancer that you never even realise you have or a slow-growing one, you get a faster growing and more aggressive version.
It’s yet to be confirmed but melanomas are thought to be particularly likely to proliferate quickly when you have sleep apnoea.
Some good news
Being the harbinger of bad news isn’t much fun so I’d like to give you some good news now. If you’ve only got mild sleep apnoea, or you just snore a bit, you probably don’t have an increased risk of illness.
In fact, if you have mild sleep apnoea, you might be able to manage your risk quite effectively with dietary changes, which will improve your overall heath and stop you from developing a more severe version of the condition.
If you’ve got severe sleep apnoea, it’s really serious but still treatable, so it’s time to see a sleep doctor and get something done about it. More good news: if you do have severe sleep apnoea and you get it treated, your risk is much, much lower.
What all this adds up to is that sleep apnoea needs to be taken seriously; it’s not just a nuisance snoring condition. Not only will treatment help make you feel better, it will also reduce your risk for all kinds of attendant bad things from happening.
Nathaniel Marshall receives funding from the Australian National Health and Medical Research Council