High blood pressure (hypertension) does not usually have any symptoms, so the only way to find out if you have it is to get your blood pressure checked.
Healthy adults aged over 40 should have their blood pressure checked at least once every 5 years.
If you're at an increased risk of high blood pressure, you should have your blood pressure checked more often, ideally once a year.
Having this done is easy and could save your life.
Where to get a blood pressure test
You can ask for a blood pressure check. You do not have to wait to be offered one.
Blood pressure testing is available:
- at your GP surgery – by a GP, practice nurse, healthcare assistant or self-service machine
- at some pharmacies
- at an NHS Health Check appointment offered to adults aged 40 to 74 in England
- in some workplaces
- at a health event
You can also test your blood pressure at home using a home testing kit.
Having a blood pressure test
A stethoscope, arm cuff, pump and dial was normally used to measure your blood pressure, but automatic devices with sensors and digital displays are commonly used nowadays.
It's best to sit down with your back supported and legs uncrossed for at least 5 minutes before the test.
You'll usually need to roll up your sleeves or remove any long-sleeved clothing so the cuff can be placed around your upper arm.
Try to relax and avoid talking while the test is carried out.
During the test:
- you hold out one of your arms so it's at the same level as your heart, and the cuff is placed around it – your arm should be supported in this position with a cushion or the arm of a chair, for example
- the cuff is pumped up to restrict the blood flow in your arm – this squeezing may feel a bit uncomfortable, but only lasts a few seconds
- the pressure in the cuff is slowly released and detectors sense vibrations in your arteries – a doctor will use a stethoscope to detect these if your blood pressure is measured manually
- the pressure in the cuff is recorded at 2 points as the blood flow starts to return to your arm – these measurements are used to give your blood pressure reading
You can usually find out your result straight away, either from the healthcare professional carrying out the test or on the digital display.
If your blood pressure is high, you may be advised to record your blood pressure at home to confirm whether you have high blood pressure.
Ambulatory (24-hour) blood pressure monitoring
Having a raised blood pressure reading in 1 test does not necessarily mean you have high blood pressure.
Blood pressure can fluctuate throughout the day. Feeling anxious or stressed when you visit your GP can also raise your blood pressure.
If you have a high reading, you may be asked to take some readings with a home blood pressure monitor, or wear a 24-hour monitor that checks your blood pressure throughout the day.
This will confirm whether you have consistently high blood pressure.
It's known as 24-hour or ambulatory blood pressure monitoring.
Home blood pressure testing
Blood pressure tests can also be carried out at home using your own blood pressure monitor.
Like 24-hour or ambulatory monitoring, this can give a better reflection of your blood pressure.
It can also allow you to monitor your condition more easily in the long term.
You can buy a variety of low-cost monitors so you can test your blood pressure at home or while you're out and about.
Measure your blood pressure twice a day, ideally in the morning and the evening, while you're sitting down.
Each time take 2 readings, 1 minute apart. Continue to measure your blood pressure twice a day for 7 days.
Your doctor or nurse will use this information to work out your average blood pressure.
It's important to make sure you use equipment that's been properly tested.
The British Hypertension Society (BHS) has information about validated blood pressure monitors that are available to buy.
Understanding your blood pressure reading
Blood pressure is measured in millimetres of mercury (mmHg) and is given as 2 figures:
- systolic pressure – the pressure when your heart pushes blood out
- diastolic pressure – the pressure when your heart rests between beats
For example, if your blood pressure is "140 over 90", or 140/90mmHg, it means you have a systolic pressure of 140mmHg and a diastolic pressure of 90mmHg.
As a general guide:
- high blood pressure is considered to be 140/90mmHg or higher (or an average of 135/85mmHg at home) – or 150/90mmHg or higher (or an average of 145/85mmHg at home) if you're over the age of 80
- ideal blood pressure is usually considered to be between 90/60mmHg and 120/80mmHg, while the target for over-80s is below 150/90mmHg (or 145/85mmHg at home)
Blood pressure readings between 120/80mmHg and 140/90mmHg could mean you're at risk of developing high blood pressure if you do not take steps to keep your blood pressure under control.