Obstructive sleep apnoea (OSA) is a common but often overlooked condition. Many people think of it as just snoring or feeling groggy during the day—but the reality is much more serious. Sleep apnoea puts significant strain on your heart and blood vessels. Left untreated, it can lead to major health problems like high blood pressure, irregular heart rhythms, stroke, heart disease, and even early death.
In recent years, researchers have learned a lot more about how and why sleep apnoea harms the cardiovascular system—and how to treat it effectively. If you or someone you love has been diagnosed with sleep apnoea, or you think you might have it, here’s what you need to know.
One of the primary reasons why sleep apnoea is dangerous in the long term is the repeated disruptions in breathing lead to a release of stress hormones that wake you up in order to re-open your airway and resume normal breathing; very useful in the short term but ruins the quality of your sleep and increases allostatic load.
1. Sleep Apnoea Significantly Increases the Risk of Stroke, Heart Disease and Early Death
Sleep apnoea is much more serious than just loud snoring or feeling tired during the day. When left untreated, it can increase your risk of major heart and brain-related health problems, including stroke and even early death.
One of the largest and most respected studies on sleep apnoea, published in the New England Journal of Medicine, found that people with untreated moderate to severe sleep apnoea were two to three times more likely to have a stroke or die early than people without it. These risks were still present even after taking into account things like weight, age, or high blood pressure. That means sleep apnoea on its own is a major health risk.
Why is this the case? Every time your oxygen drops and your body jolts awake, it adds stress to your heart, blood vessels, and brain. Over time, this increases your risk of:
- High blood pressure
- Heart rhythm problems
- Stroke
- Heart disease
- Shorter life expectancy
The good news is that these risks drop significantly with the right treatment—especially if sleep apnoea is caught early. Sometimes high blood pressure is immediately treated by CPAP therapy.
2. It’s Not Just About How Often You Stop Breathing—It’s About How Badly
Traditionally, sleep apnoea is measured using something called the Apnoea-Hypopnoea Index (AHI). This number tells you how many times per hour you stop breathing (either partially or fully) during sleep. A higher AHI means more breathing problems during the night.
But recent research has shown that AHI doesn’t always tell the whole story. Two people can have the same AHI but very different health outcomes because what really matters is how long and how deeply your oxygen drops during these events—what scientists call the hypoxic burden.
Studies have found that people with a high hypoxic burden—meaning their oxygen levels drop a lot and stay low for longer—are at a much higher risk of heart disease and early death, even if their AHI is relatively low. So, if you’ve been told your AHI is “moderate” or “borderline,” that doesn’t always mean your risk is low. A full sleep study that looks at oxygen levels throughout the night is a better way to understand your personal risk.
3. Your Heart’s Reaction to Sleep Apnoea Matters Too
Another important factor that’s often overlooked is how your heart rate responds during sleep apnoea events.
When your breathing is blocked, your body goes into a kind of stress response—your heart rate speeds up suddenly when you jolt awake and start breathing again. This change in heart rate is known as delta heart rate.
Studies have shown that a bigger change in heart rate (more than 10 beats per minute) during these events is linked to a higher risk of cardiovascular problems. People with a large delta heart rate who start using a CPAP machine (the most common treatment for sleep apnoea) have a much lower risk of heart disease—by as much as 59% compared to those who go untreated.
4. Treatment with CPAP Can Dramatically Reduce Your Heart Risks
The most effective treatment for moderate to severe sleep apnoea is a device called a CPAP (Continuous Positive Airway Pressure) machine. This machine gently blows air through a mask to keep your airway open while you sleep. It may take some getting used to, but it can make a huge difference to your heart health. CPAP can:
- Stop your breathing from being blocked
- Keep your oxygen levels stable
- Reduce stress on your heart and blood vessels
- Help you feel more rested and alert during the day
- Lower your risk of heart disease, stroke, and early death
People using CPAP often report more energy, better mood, improved concentration, and better control of other health conditions like high blood pressure or diabetes. In many cases, CPAP doesn’t just improve sleep—it improves your heart health and your life.
Final Thoughts: Protect Your Heart by Treating Sleep Apnoea
Sleep apnoea is common, and it’s serious. But it’s also very treatable.
If you or someone you know snores loudly, feels exhausted during the day, or has been told they stop breathing in their sleep, don’t wait. Call Home Sleep for a comprehensive sleep study conducted in the privacy and comfort of your own home. Getting tested for sleep apnoea is simple, and treatment can be life-changing.
The sooner you act, the sooner you can sleep better, feel better—and protect your heart for years to come.
References
- Yaggi HK, Concato J, et al. (2005). Obstructive Sleep Apnea as a Risk Factor for Stroke and Death. New England Journal of Medicine, 353(19), 2034–2041. https://www.nejm.org/doi/full/10.1056/NEJMoa043104
- Labarca G, et al. (2023). Hypoxic burden and cardiovascular mortality in sleep apnea. European Heart Journal. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11267182/
- Azarbarzin A, et al. (2013). The impact of heart rate response to sleep-disordered breathing on cardiovascular disease. PLOS Medicine, 10(10), e1001599. https://journals.plos.org/plosmedicine/article?id=10.1371%2Fjournal.pmed.1001599
- Wang X, et al. (2017). Obstructive sleep apnoea and risk of cardiovascular disease and all-cause mortality: a meta-analysis. BMJ Open, 7(12), e013983. https://bmjopen.bmj.com/content/7/12/e013983
- Roca GQ, et al. (2024). Obstructive Sleep Apnea and Cardiovascular Events in Young Adults. Journal of the American Heart Association, 13(1), e033506. https://www.ahajournals.org/doi/10.1161/JAHA.123.033506