High blood pressure (hypertension)

Expert reviewer, Dr Tim Cripps, Consultant Cardiologist
Next review due May 2022

High blood pressure (hypertension) is a common medical condition where the pressure inside your arteries is higher than it should be. If you have it, you probably won’t get any symptoms but you’re more likely to get serious problems like heart disease, a stroke or kidney disease.

There’s a lot you can do yourself, and there are good treatments available to reduce high blood pressure.

About high blood pressure

Every time your heart beats, it pumps blood under pressure to the rest of your body through your arteries. You need some pressure to keep your blood moving, but if it’s consistently too high, it puts extra strain on your heart and blood vessels. Other parts of your body, such as your brain and your kidneys may also be affected by high blood pressure.

Sometimes high blood pressure is caused by another health problem you already have. But most of the time there’s no obvious cause. See our Section on causes below for more information.

Blood pressure is measured at two points:

  • the highest level, when your heart muscle contracts and pumps blood out through the arteries – this is called systolic blood pressure
  • the lowest level, when your heart relaxes between beats and fills with blood – this is called diastolic blood pressure

Your overall blood pressure reading combines these and is shown as two numbers measured in ‘millimetres of mercury (mmHg)’. A reading of around 120/80mmHg is seen as healthy – above 140/90mmHg is considered high.

Blood pressure chart

Symptoms of high blood pressure

Most people with high blood pressure don’t have any symptoms and aren’t aware of their condition. It’s usually discovered when you have your blood pressure measured, perhaps as part of a health assessment.

If you have high blood pressure and it causes complications, you may get symptoms linked to those. See our Section on complications below for more information.

Diagnosis of high blood pressure

The only way to know if you have high blood pressure is to have it measured. It’s good to get your blood pressure checked at least every five years. You may be able to get this done at your local pharmacy. Everyone should know their blood pressure.

Measuring blood pressure

The latest automated, digital devices make it quick and easy to check your blood pressure. Or your doctor might take a manual reading, using a stethoscope held against your arm to listen to the blood flow. Try to relax – it may be a little uncomfortable but that’s only for a few moments. To watch how blood pressure is taken, see our Video above.

Your GP or nurse will probably check your blood pressure reading several times during an appointment. If your blood pressure is high, they may recommend you have more readings over a longer period to make a definite diagnosis. There are two ways to do this.

  • Wearing a device on your arm for 24 hours as you carry on normal activities. This is called ambulatory blood pressure monitoring (ABPM). See our FAQ on 24-hour monitoring below.
  • Measuring your own blood pressure yourself every morning and evening for four to seven days. This is known as home blood pressure monitoring (HBPM). You should measure your blood pressure after sitting in a quiet room for five minutes.

You can buy your own device for measuring your blood pressure at home. The British and Irish Hypertension Society tests available devices and validates those that are suitable for use at home. You can find a list of devices they’ve validated on their website.

Further tests

If you have high blood pressure, your doctor will want to find out if there’s a reason for this. They’ll also want to see if it has done any harm, especially to your heart or kidneys.

Your doctor will ask about your general health, your family’s medical history, what medicines you take, and any physical changes you’ve noticed. They may also ask about your weight, diet, exercise and drinking habits and examine you.

You may be offered further tests, including:

  • a urine test – to check for protein or blood in your urine that could be a sign of kidney damage
  • a blood test – to check your cholesterol and blood sugar levels, and to check how well your kidneys are working
  • an electrocardiogram (ECG) – to check how your heart is working
  • an examination of the back of your eyes with an ophthalmoscope – to check whether the blood vessels there are healthy

If your blood pressure is very high (over 180/110mmHg) or your GP suspects it’s caused by a serious condition, you may be referred to a specialist. They may also refer you to a specialist if you have high blood pressure and you are under 40.

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Causes of high blood pressure

For most people with high blood pressure there’s no obvious cause. This is called ‘primary’ or ‘essential’ hypertension. There are some things which increase your risk of developing this type of high blood pressure. These include:

  • your age – the risk increases as you get older
  • having someone in your close family with high blood pressure
  • being overweight or obese
  • eating too much salt
  • drinking too much alcohol
  • not getting enough exercise
  • anxiety and stress

In about one in 20 people with high blood pressure, it’s linked to an underlying medical issue. This is called ‘secondary’ hypertension. Causes of secondary hypertension include:

Some medicines can also increase your blood pressure. These include decongestant cough and cold remedies, anti-inflammatories, steroids and oral contraceptives. Always read the information that comes with your medicine carefully. Illegal drugs such as cocaine, and herbal remedies that contain liquorice can also raise your blood pressure.

Treatment of high blood pressure

There are several things your doctor will consider in deciding how best to treat you. These include:

  • your age
  • your ethnic group (especially if you are of African or Caribbean origin)
  • any medical conditions you already have
  • what risk you face of heart disease and stroke
  • the possible causes of your high blood pressure
  • how high your blood pressure is

Lifestyle changes

There are some changes you can make to live more healthily and help reduce your blood pressure. Your doctor will encourage you to make these changes as part of your treatment.

  • Lose excess weight. Aim to get your waist down to less than 102cm (40 inches, if you’re a man) or less than 88cm (35 inches, if you’re a woman). Our video below shows you how to measure your waist.
  • Be more physically active. Note that things like weightlifting and weight training can make high blood pressure worse so may be unsuitable.
  • Eat a healthy, balanced diet, including at least five portions of fruit and vegetables a day. It’s also good to eat at least one portion of oily fish, such as salmon, sardines and mackerel, every week.
  • Eat less salt – you should have less than 5g (one teaspoon) a day.
  • Cut down on alcohol – stick to recommended guidelines.
  • Drink less coffee and other caffeinated drinks like cola.

Stress can make your blood pressure go up, so learn how to manage stress.

Stopping smoking may not have a direct impact on your blood pressure, but it does reduce the risk of complications like heart disease and stroke.


There are several different medicines that can be used to lower your blood pressure. Your GP will offer you the medicines which are most suitable for you. They will take into account such things as your age, ethnicity, how high your blood pressure is and your general health.

Your GP may well start you on a combination of two medicines to reduce your blood pressure. It can take time to find the medicines that work for you.

The medicines most commonly used to treat high blood pressure are listed here.

  • Angiotensin-converting enzyme inhibitors (ACE inhibitors, for example, ramipril, lisinopril) – these relax and widen blood vessels.
  • Angiotensin-II receptor blockers (ARBs, for example candesartan, losartan, valsartan) – these work in a similar way to ACE inhibitors.
  • Calcium-channel blockers (CCBs, for example, amlodipine, diltiazem) – these relax and widen your arteries so your heart receives a better blood supply and needs to do less work to pump it round your body.
  • Thiazide diuretics (for example, bendrofluazide, indapamide) – these act on your kidneys to make more urine, so leaving less excess fluid in your blood.

If these aren’t suitable for you, or if they don’t work well enough, your doctor may prescribe other medicines to treat your high blood pressure. For instance, sometimes beta-blockers may be suitable, although these are no longer used as one of the main treatments for high blood pressure.

Always carefully read the information that comes with your medicines, and if you have any questions about taking them, ask your pharmacist.

Your doctor may suggest you regularly monitor your blood pressure at home as part of your treatment.

Complications of high blood pressure

Having high blood pressure increases your risk of getting complications, including:

These problems usually take many years to develop. The good news is that, if you control your blood pressure with medicines and changes to your lifestyle, you can reduce the risk of them ever happening.

Special considerations for high blood pressure


High blood pressure is a particular issue if you have diabetes. Both hypertension and diabetes increase the risk of kidney disease and cardiovascular disease. If you have diabetes, you should get your blood pressure measured at least once a year.


If you’re pregnant, you’ll have your blood pressure checked regularly. This is because having high blood pressure during pregnancy may cause problems for you and your baby. It may be a sign of a condition called pre-eclampsia.

If you were being treated for high blood pressure before you were pregnant, your doctor may recommend changing your medicines during your pregnancy.

Frequently asked questions

  • Monitoring your blood pressure frequently during normal activities can give a more accurate measurement than readings taken at the doctor’s, when you may feel nervous. So, your doctor may suggest you have 24-hour (or ambulatory) monitoring.

    For this, you need to wear a small digital machine on a belt round your waist and an inflatable cuff on your upper arm for a full 24 hours. Your blood pressure will be measured at regular intervals – perhaps twice an hour during the day and hourly overnight. You should carry on your normal activities, but you’ll need to avoid getting the equipment wet. Your nurse or GP will explain what the test involves, and will be able to answer any questions you have about it.

  • There are a variety of medicines that can lower blood pressure. Your doctor will offer you the medicines which are likely to be the best for you in your particular circumstances. There are national guidelines to help them make this decision.

    If your medicine doesn’t lower your blood pressure enough, or you’re getting side-effects, your doctor may suggest making a change. This may be changing the dose, adding another medicine or trying a different combination of medicines.

    If you have any questions about the medicines you’re taking, you can ask your pharmacist.

  • If you have a car or motorcycle licence, you don’t have to tell the Driver and Vehicle Licensing Agency (DVLA) that you have high blood pressure. Having high blood pressure doesn’t usually cause any symptoms which affect your ability to drive. However, you shouldn’t drive if the medicines you’re taking give you side-effects which affect your driving ability. Talk to your GP if this happens – they may be able to change your medicines.

    If you have a licence to drive a bus, coach or lorry then you must tell the DVLA that you have high blood pressure. If your blood pressure is very high you may need to stop driving until it is under control.

    It’s up to you to tell the DVLA about any condition that may reduce your ability to drive safely. You should also check your insurance to make sure you’re still covered after being diagnosed with high blood pressure.

  • People sometimes wonder what a dangerously high blood pressure would be. Having high blood pressure is linked to an increased chance of serious health conditions such as heart attack, stroke and kidney disease. So, in a sense, all high blood pressure could be said to be ‘dangerous’.

    However, if by ‘dangerous’ we mean something which needs immediate treatment, this would be a blood pressure of 180/110mmHg or above. If your blood pressure is this high, your GP will probably refer you to a specialist immediately.

    If you’re concerned about your blood pressure, contact your GP for advice.

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Related information

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    • Hypertension. Medscape., updated February 2019
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  • Reviewed by Dr Kristina Routh, Freelance Health Editor, Bupa Health Content Team, May 2019
    Expert reviewer, Dr Tim Cripps, Consultant Cardiologist
    Next review due May 2022