High blood pressure and stroke
High blood pressure is the biggest risk factor for stroke. Lifestyle changes and medication can help lower blood pressure and reduce your risk of stroke.
What is high blood pressure?
Your heart pumps blood all around your body. Blood pressure is a measure of how strongly the blood presses against the walls of your arteries. If this pressure is too high it puts a strain on your arteries and your heart. If it’s not controlled it can increase your risk of having a stroke or heart attack.
A diagnosis of high blood pressure means that your blood pressure stays high over a long period. The medical term for this is hypertension.
Your blood pressure can go up and down over the course of a day, such as during exercise or sleep. These short-term changes are not likely to cause stroke. But when your blood pressure stays high over a long period of time, this leads to damage to the blood vessels and can eventually cause a stroke.
How is high blood pressure diagnosed?
You are usually diagnosed with high blood pressure if it is consistently higher than 140/90 mmHg.
If you have diabetes, you may be treated with medication if your blood pressure is consistently above 130/80 mmHg and you have any complications of diabetes such as eye or kidney problems.
How is blood pressure measured?
Measuring your blood pressure is quick, simple and painless, and can be carried out at your doctor’s surgery or at some pharmacies. A stethoscope, arm cuff, pump and dial was used until recently to measure blood pressure, but automatic devices with sensors and digital displays are now in common use.
Understanding your blood pressure reading
Your blood pressure reading is recorded as two numbers. The first number is the greatest pressure your arteries experience when your heart beats (this is called systolic pressure). The second number is the lower pressure when your heart relaxes between beats (diastolic pressure). Both pressures are measured in millimetres of mercury, written as ‘mmHg’.
The ideal blood pressure is between 90/60 mmHg and 120/80 mmHg. Both numbers are equally important, and blood pressure is counted as being high if either number is high.
How often should my blood pressure be checked?
All adults should have their blood pressure checked regularly. If you have normal blood pressure, try to be checked at least once every five years, preferably more often.
Your blood pressure should be checked more frequently if it is nearer 140/90 mmHg, as you have a higher risk of developing high blood pressure. If you’ve had a high or borderline reading in the past, your blood pressure should be measured at least once a year.
Women taking the contraceptive pill, who are pregnant or taking hormone replacement therapy (HRT), also need to have their blood pressure checked more often.
And if you are already taking medication to control your blood pressure, you will need to have it checked regularly. You might be offered ambulatory or home monitoring.
If you wish to buy a blood pressure monitor, you can find information and a list of validated monitors on the British Hypertension Society website. If you are using a machine at home, you will usually be advised to take your blood pressure twice a day, at the beginning and the end of the day to start with.
If you are thinking of buying a home monitor, discuss with your doctor how it can help you achieve your target blood pressure.
Treating high blood pressure
Many people can lower their blood pressure by making changes to their lifestyle. If you are overweight, losing some weight can make a big difference. Doing some more exercise, eating healthier food, and reducing alcohol can also cause a big improvement in blood pressure levels.
You may be advised to take medication, especially if you have some additional risk factors. To help you make a decision about medication, your doctor will assess your personal risk of developing stroke or heart disease in future. They look at whether your high blood pressure has caused problems in the body already. You may have a blood test, a urine test, and an electrocardiogram (ECG) to check for heart problems.
If your blood pressure is consistently above 140/90 mmHg (or 135/85 mmHg at home) but your overall risk of a stroke is low you’ll be advised to make some changes to your lifestyle such as losing weight or stopping smoking.
If your blood pressure is consistently above 140/90 mmHg (or 135/85 mmHg at home) and your risk of stroke is high, you’ll be offered medication to lower your blood pressure and advice about making lifestyle changes.
If your blood pressure is consistently above 160/100 mmHg, you’ll be offered medication to lower your blood pressure, even if your risk of a stroke is low, as well as advice on making lifestyle changes.
The medication you take will be tailored to your individual needs. The medication recommended for you at first will depend on your age and ethnicity. You might take one type of medication or a combination of two or more types.
The main groups of blood pressure medication are:
- ACE (angiotensin-converting enzyme) inhibitors.
- Angiotensin-2 receptor blockers.
- Calcium channel blockers.
- Thiazide-like diuretics.
These are the most commonly used ones, but other types are also available, including beta blockers.
To give yourself the best possible chance of lowering your blood pressure, take your medication according to the packet’s instructions and as advised by your doctor.
Read our PDF guide 'High blood pressure and stroke', for more on the main types of blood pressure medications.
How long will I be on medication?
The aim of the medication is to keep your blood pressure low and stable over many years. This helps to keep your blood vessels healthy and reduce the risk of a stroke.
Some people may be advised to continue taking medication for high blood pressure for the rest of their lives. Talk to your doctor, pharmacist or stroke nurse to find out more about what is causing your high blood pressure, and the best treatment options for you.
These tips for healthy lifestyle choices can also help to lower your blood pressure:
- Reduce your salt intake. Don’t add salt to your food, and avoid processed foods that contain a lot of salt.
- You should have your blood pressure checked and your medication reviewed at least once a year.
- Eat at least five portions of fruit and vegetables each day.
- Lose weight if you need to.
- Reduce your caffeine intake.
- Give up smoking.
- Reduce your alcohol intake and avoid binge drinking.
- Be more active.
- Reduce your stress levels and take time to relax.
- Try to get at least six hours sleep a night.
- Download Blood pressure and stroke guide (PDF)
- Download Getting active after a stroke guide (PDF)
- Download How to reduce your risk of a stroke guide (PDF)
- Download Diabetes and stroke guide (PDF)
Blood Pressure (UK)
Phone: 020 7882 6218
Provides a wide range of information on high blood pressure.
British Heart Foundation (BHF)
Phone: 0300 330 3311
The helpline is staffed by cardiac nurses.
British Hypertension Society
Publishes a list of blood pressure monitors.
Disclaimer: The Stroke Association provides the details of other organisations for information only. Inclusion on My Stroke Guide does not constitute a recommendation or endorsement.