What causes a stroke?

A stroke occurs when blood flow to a part of your brain is cut off. Without the oxygen in blood, brain cells start to die rapidly. It turns out there are particular conditions that predispose you to risk of experiencing a stroke. Some of the most common stroke causes include high blood pressure, high cholesterol, diabetes, and smoking. People with heart rhythm disturbances and other heart diseases are also at risk. In this article, we will look into the most common stroke causes in detail.

In general, risk factors can be categorized in conditions that are manageable and treatable, and risk factors that are non-modifiable and unfortunately cannot be affected.

Stroke causes that can often be manageable:

High blood pressure

This is among the most common risk factors that expedites development of stroke. High blood pressure contributes to development of atherosclerosis (plaques of cholesterol deposited on walls of vessels) which finally are responsible for ischaemic stroke. It also contributes to weakening of brain blood vessels (known as amyloid angiopathy) which may lead to rupture of vessel and brain haemorrhage. Your optimal blood pressure should be around or even below 120/80 mmHg, but no higher than 140/90 mmHg (these are general guidelines and cannot be perceived as medical advice).

High cholesterol

It contributes to the development of atherosclerosis. Although your cholesterol levels are partially determined by your heredity, in case of elevated cholesterol levels, a lot can be done to normalize them. Options vary from diet to specific medication. It is very important to address this issue as early as possible as high cholesterol doesn’t have specific symptoms and develop atherosclerosis unnoticed. Some people may develop a high level of cholesterol at a very young age. It is recommended to check your cholesterol levels according to guidelines in each country.


Smoking or chewing tobacco raises your odds of a stroke. Nicotine makes your blood pressure go up and smoke causes a fatty buildup (atherosclerotic plaque) in your main neck artery. It also thickens your blood and makes it more likely to clot. Exposure to secondhand smoke also puts you at risk.


It is often accompanied by high blood pressure and people with diabetes are more likely to be overweight. Similarly as factors above, diabetes contributes to the development of atherosclerosis and it raises the chance of a stroke.

Heart disease

This includes defective heart valves, atrial fibrillation, or irregular heartbeat, which causes up to 25% of all strokes among the very elderly. These heart diseases carry a risk of development of blood clots within the heart which can subsequently draw away and travel by blood stream into brain vessels causing occlusion and circulation disruption.

Other stroke causes that are often manageable include being obese or overweight, having a sedentary lifestyle, heavy drinking and substance abuse, obstructive sleep apnea. Also, medications such as overuse of blood-thinning medicine, hormones or birth control pills have also been linked to a higher chance of stroke.

Non-modifiable stroke causes:


The set of the genes that you have born with are not modifiable for now, however there are promising techniques (including CRISPR Genome editing) that may allow doctors to modify even those in the foreseeable future.

Increasing age

Generally, the chances go up the older you get. People over the age of 50 are increasingly at risk. Stroke for younger people is much rarer, and can happen due to abnormal blood conditions, inherited predispositions or substance abuse. There are few reports suggesting that novel SARS-CoV-2 virus responsible for COVID-19 disease can make blood clots more prone to form and cause strokes in younger and previously well individuals.


Men are more likely than women to experience strokes. Women are usually older when they have strokes. This can be explained by the protective effect of estrogens which are at high levels in women’s organisms until menopause. That’s why women usually get strokes at an older age and they’re more likely to die of strokes.

These are the most common stroke causes to take into consideration. Furthermore, there are certain lifestyle and influential factors to consider to help prevent a stroke from happening. It is also important to manage the aforementioned medical factors. To learn more about stroke prevention, read in our article “What can help prevent a stroke?”.

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