Overview
A blood pressure test checks if your blood pressure is healthy, or if it's high or low.
Blood pressure is the term used to describe the strength with which your blood pushes on the sides of your arteries as it's pumped around your body.
High blood pressure (hypertension) can increase your risk of developing serious problems such as heart attacks and strokes.
Low blood pressure (hypotension) is not usually a problem, although it can cause dizziness and fainting in some people.
Having this quick test is the only way to find out what your blood pressure is and it could save your life.
When should I get my blood pressure tested?
You can ask for a blood pressure test if you're worried about your blood pressure at any time.
If you have been diagnosed with high or low blood pressure, or you have a high risk of developing either, you may need more frequent checks of your blood pressure.
You can get your blood pressure tested at a number of places, including:
- at your local GP surgery
- some pharmacies
- some workplaces
How blood pressure is tested
Blood pressure machines vary, but they're all a type of measuring device, which often have an arm cuff attached to it.
The cuff is usually wrapped around your upper arm and filled with air until it feels tight. This can feel uncomfortable but it only lasts a few seconds.
It's important to relax and not talk during this time, because this is when your blood pressure is measured.
If a healthcare professional is doing this for you, they may also use a stethoscope to record your blood pressure.
An automatic device usually picks up the measurements from sensors in the arm cuff, which are sent to a digital display.
You should get the results straight away.
Home blood pressure monitoring
Blood pressure is measured in millimetres of mercury (mmHg) and is given as 2 numbers:
- systolic pressure – the pressure when your heart pushes blood out around your body
- diastolic pressure – the pressure when your heart rests between beats and blood is pushed around your heart
The highest number is always the systolic pressure and it's always given first. For example, a blood pressure given as "120 over 80" or 120/80mmHg means a systolic pressure of 120mmHg and a diastolic pressure of 80mmHg.
Understanding your blood pressure reading
Your blood pressure reading can tell you how healthy your blood pressure is.
As a general guide:
- normal blood pressure is considered to be between 90/60mmHg and 120/80mmHg (this applies if it's measured at home or at a GP surgery or clinic)
- high blood pressure is considered to be 135/85 or higher if your reading was taken at home, or 140/90mmHg or higher if your reading was taken at a GP surgery or clinic
- low blood pressure is considered to be lower than 89/59mmHg or lower
If your reading is between 120/80mmHg and 140/90mmHg, you may be at risk of developing high blood pressure in the future. There are things you can do to help prevent high blood pressure.
Testing your blood pressure at home
Your GP may suggest 24-hour or ambulatory blood pressure monitoring (ABPM) if they think you may have high blood pressure (hypertension).
ABPM tests your blood pressure regularly over 24 hours, by using a cuff attached to a portable device that's worn on your waist.
You can continue with your daily activities during this time.
If you want to regularly check your blood pressure at home, you can buy a machine.
Blood pressure devices for home use
If you want to check your blood pressure regularly at home, you can buy a digital blood pressure machine.
Choose a machine that measures your blood pressure at your upper arm, not your wrist or finger.
Let your GP know you're doing this.
Find out more:
The British Heart Foundation: How to choose a blood pressure monitor and measure your blood pressure at home
Blood Pressure UK: How to measure your blood pressure at home