Stroke occurs when blood flow to the brain is interrupted. There are many reasons that this can happen, but one of the biggest culprits is high blood pressure, as this can weaken the arteries in the brain and cause them to burst or clog more easily. This makes high blood pressure the biggest single risk factor for stroke. (1)

How common is high blood pressure?

Around 26% of the world’s population have high blood pressure (or hypertension). It affects around one billion individuals and causes an estimated 9.4 million deaths every year. Yet millions more don’t even know they have it. (2,3)

What’s the difference between primary and secondary high blood pressure?

The majority of adult cases (90–95%) are classed as primary hypertension, which may be the result of genetic factors i.e. it has been passed on to you by a relative. Only a small percentage of cases are secondary (up to 10%). These have a variety of different causes, including taking certain medications, misusing illegal drugs or having a pre-existing medical condition, such as weak kidneys. (4)

How do you know if you have high blood pressure?

If you’ve ever had your blood pressure taken, you will have been given two numbers. The first number is known as your systolic blood pressure; the second is your diastolic blood pressure. A normal reading would be lower than 120/80. If either reading is higher than this, you could have, or be developing, high blood pressure.
Usually, once your systolic pressure is under control, your diastolic pressure comes down too. (1)

What causes high blood pressure?

There are many things that can contribute to high blood pressure. The risk rises as we get older and it is more common in men, especially black males. You also have more chance of developing the condition if it runs in your family, if you are overweight, smoke, drink too much alcohol or eat a diet high in salt. High blood pressure can also develop in pregnancy; and if you suffer from long-term conditions such as kidney disease or diabetes. (6)

What are the symptoms of high blood pressure?

The reason people don’t always know they have high blood pressure is because there are often few, or no, symptoms. You may have headaches, shortness of breath or nosebleeds. But you may experience nothing at all. Damage could be happening to your arteries without you even knowing it, increasing your risk of stroke. That’s why it’s so important, for those over age 18, to have blood pressure checked once a year. (6)

What can I do to minimise my risk of stroke?

As well as regular blood pressure checks, you can reduce your risk of stroke by keeping your blood pressure low. This is easily achieved by living a healthy lifestyle with a good diet and regular exercise, and by taking medication, if advised by your doctor. Remember, the lower your blood pressure, the lower your risk of stroke. (1)


1. WHO. A global brief on hypertension. Geneva: World Health Organisation, 2013.

2. Benjamin EJ, Blaha MJ, Chiuve SE, et al, for the American Heart Association Statistics Committee and Stroke Statistics Subcommittee. Heart disease and stroke statistics-2017 update: a report from the American Heart Association. Circulation. 2017 Mar 7. 135 (10):e146-e603.

3. Kearney PM, Whelton M, Reynolds K, Muntner P, Whelton PK, He J. Global burden of hypertension: analysis of worldwide data. Lancet. 2005 Jan 15-21. 365 (9455):217-23.

4. [Guideline] Mancia G, Fagard R, Narkiewicz K, et al. 2013 ESH/ESC Guidelines for the management of arterial hypertension. 23rd European Meeting on Hypertension & Cardiovascular Protection. Available at

5. James PA, Oparil S, Carter BL, et al. 2014 Evidence-Based Guideline for the Management of High Blood Pressure in AdultsReport From the Panel Members Appointed to the Eighth Joint National Committee (JNC 8). JAMA. 2014;311(5):507–520. doi:10.1001/jama.2013.284427

6. Katakam R, Brukamp K, Townsend RR. What is the proper workup of a patient with hypertension?. Cleve Clin J Med. 2008 Sep. 75(9):663-72.