Sleep Apnoea Can Lead To Stroke; How The Deadly Conditions Are Linked

The incidence of stroke has been rising across the world. According to a study published in Lancet Neurology, India reported over 1.25 million new stroke cases in 2021 compared to 650,000 in 1990. The report also states that the prevalence of stroke in the country increased by 47 per cent, from 4.4 million in 1990 to 9.4 million in 2021. Stroke is a medical emergency, which happens when blood flow to the brain is interrupted. This causes the brain cells to die due to lack of oxygen. There are various causes of stroke. From atherosclerosis (hardened arteries) to heart defects, high blood pressure, sleep apnoea and more, a stroke can happen due to different conditions.

Sleep apnoea is a condition wherein an individual stops and starts breathing repeatedly while they're asleep. This can cause loud snoring, daytime fatigue, waking up with shortness of breath and other symptoms. People who have sleep apnoea have an increased risk of suffering a stroke.

How Sleep Apnoea Increases Risk Of Stroke

Here are some pointers that explain how sleep apnoea and stroke are linked.

Reduced Oxygen Levels at Night

Sleep apnoea causes a person to stop breathing several times while they're asleep. This leads to low oxygen levels in the blood. When the oxygen supply reduces, the cells and tissues in the brain suffer from hypoxia. The brain is very sensitive to oxygen shortages and when there are repeated episodes of low oxygen, it can damage blood vessels in the brain and make them more prone to blockage and rupture, which can lead to a stroke.

High Blood Pressure

When breathing stops during sleep apnoea, the body reacts by releasing stress hormones. This increases the heart rate and blood pressure suddenly during and after these episodes. Over time this stress can lead to high blood pressure, which is a major risk factor for strokes. High blood pressure damages the arteries that supply the brain, making it easier for blockage or bleeding, both of which can cause a stroke.

Increased Risk of Irregular Heart Rhythms

Sleep apnoea is linked to abnormal heart rhythms, which can cause blood clots to form in the heart. These clots can travel to the brain and block blood flow, causing a stroke. Studies show that the risk of stroke is much higher among people who have both sleep apnoea and atrial fibrillation.

Night-Time Strokes

Studies show that a significant number of strokes, especially ischemic strokes occur at night or right after sleep. Researchers believe that sleep apnoea can trigger strokes during sleep by causing drops in oxygen and sudden blood pressure surges.

Shared Risk Factors

Both sleep apnoea and stroke have certain risk factors in common, such as obesity, older age, high blood pressure, diabetes and smoking. People with these risk factors are more likely to have sleep apnoea, which adds to their overall risk for stroke. For example, elderly people with severe sleep apnoea have been found to have more than double the risk of stroke compared to those without sleep apnoea, even after taking other health issues into account.

Untreated Sleep Apnoea

Sleep apnoea not only increases the risk of having a first stroke, but it also leads to poorer recovery and a higher risk of another stroke. Untreated sleep apnoea can worsen your disability and increase your risk of death after a stroke. Treating sleep apnoea using devices like CPAP can help lower these risks and improve recovery after a stroke.

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