- When blood is pumped by the heart around the body, the pressure of the blood pushing against the walls of blood vessels changes.
- Your blood pressure changes throughout the day depending on many factors including your general health and activity levels.
- Blood pressure can be measured manually, with a blood pressure cuff and stethoscope, or with an automated blood pressure machine.
- High blood pressure can increase your risk of many health conditions, especially heart disease.
- Low blood pressure does not always cause problems, but if it does, you should speak to your doctor about ways to manage it.
What is blood pressure?
As blood is pumped by the heart around the body, the pressure with which it pushes against the walls of blood vessels changes.
When the heart squeezes blood into the arteries, the pressure goes up.
When the heart is relaxed, the pressure is lower.
Your blood pressure is a measurement taken of the highest reading and the lowest reading. It is given as 2 figures highest (systolic) over lowest (diastolic).
- Systolic is the pressure in the artery as the heart contracts (squeezes). This is represented by the first number.
- Diastolic is the pressure in the artery when the heart is relaxing and being filled with blood. This is represented by the second number.
Your blood pressure changes throughout the day depending on many factors including your general health and activity levels.
How is blood pressure measured?
Blood pressure is measured in is millimetres of mercury (written as mmHg).
You can have your blood pressure measured by your doctor or nurse, and in some pharmacies. You can also purchase a blood pressure monitor to use at home, but it’s a good idea to ask your doctor if it’s necessary.
A doctor or medical professional may use a manual blood pressure cuff, together with a stethoscope, to measure your blood pressure. Automatic blood pressure machines are also available.
In either case, the process is similar:
- Remove any tight clothing from your upper arm.
- Wrap a blood pressure cuff around your upper arm, positioning it according to any instructions or diagrams printed on the cuff.
- Support the arm so it is at about the level of your heart.
- Press the button to start measuring your blood pressure.
If your doctor is measuring your blood pressure manually, they will begin to inflate and then deflate the cuff, while using a stethoscope to listen to the pulse on the inside of your elbow.
You will feel pressure over your upper arm while the cuff is inflated. It can be a little uncomfortable, but it shouldn’t hurt.
Your doctor may measure your blood pressure a total of 3 times at 1 – 2 minute intervals. This will help them get a correct reading.
You should be seated and relaxed for a few minutes before measuring your blood pressure. You should keep your legs uncrossed.
Caffeine and smoking can also raise your blood pressure reading, so it’s a good idea to avoid them for at least 2 hours before measuring your blood pressure.
What is high blood pressure (hypertension)?
Generally, if a person has a blood pressure reading greater than 140/90mmHg taken at least 2 different times, they have high blood pressure. Your doctor may confirm this using a 24-hour blood pressure measurement or getting you to measure your blood pressure at home.
Most people with high blood pressure have no symptoms, and may feel quite well. This is why it’s important to see your doctor and have your blood pressure checked regularly, especially if you have one or more of the known risk factors.
Find out more about high blood pressure.
ARE YOU AT RISK? — Are you at risk of type 2 diabetes, heart disease or kidney disease? Use the Risk Checker to find out.
What is low blood pressure (hypotension)?
For most people, low blood pressure is below 90/60mmHg.
For some people, low blood pressure is a sign of good health. These are generally people who are very fit and who have a slow pulse. For other people, low blood pressure is a problem. This could be because it increases their risk of falls or because it is a sign of an underlying medical condition.
Find out more about low blood pressure.
What is a healthy or ‘normal’ blood pressure?
Your doctor will tell you what is healthy for you, based on your medical history.
For most people, a healthy blood pressure reading is:
- a systolic blood pressure under 140mmHg — when the heart contracts (squeezes)
- a diastolic blood pressure under 90mmHg — when the heart relaxes
Around 120/80mmHg is often considered a typical blood pressure reading.
How can I lower my blood pressure?
The following steps towards a healthier lifestyle can help you lower your blood pressure and keep it at a healthy level:
- exercise regularly
- follow a healthy diet
- reduce your salt intake
- lose weightif you have overweight or obesity
- limit alcohol
- quit smoking, if you smoke
Find out more about how to lower your blood pressure.
Resources and support
Download the Heart Foundation blood pressure action plan for advice on how to manage your blood pressure and stay healthy.
The Heart Research Institute provides a guide to healthy foods to lower your blood pressure.
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Last reviewed: December 2022