High blood pressure (hypertension)


High blood pressure (hypertension)


High blood pressure (hypertension)


High blood pressure (hypertension) means that your blood pressure is continually higher than the recommended level. It rarely has noticeable symptoms.

Around 30% of people in England have high blood pressure but many don't know it. If left untreated, high blood pressure increases your risk of a heart attack or stroke. It is often referred to as a "silent killer".

The only way of knowing there is a problem is to have your blood pressure measured. 

All adults should have their blood pressure checked at least every five years. If you haven’t had yours measured, or you don’t know what your blood pressure reading is, ask your GP to check it for you.

What is high blood pressure?

Blood pressure is measured in millimetres of mercury (mmHg) and is recorded as two figures:

systolic pressure – the pressure of the blood when your heart beats to pump blood out

diastolic pressure – the pressure of the blood when your heart rests in between beats, which reflects how strongly your arteries are resisting blood flow


For example, if your GP says 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.

You are said to have high blood pressure (medically known as hypertension) if readings on separate occasions consistently show your blood pressure to be 140/90mmHg or higher.

A blood pressure reading below 130/80mmHg is considered to be normal.

Who is most at risk?

Your chances of having high blood pressure increase as you get older. There is often no clear cause of high blood pressure but you are at increased risk if you:

are overweight

have a relative with high blood pressure


are of African or Caribbean descent

eat too much salt

don't eat enough fruit and vegetables

don't do enough exercise

drink too much coffee (or other caffeine-based drinks)

drink too much alcohol 

are aged over 65

If you fall into any of the groups listed above, consider making changes to your lifestyle to lower your risk of high blood pressure. Also consider having your blood pressure checked more often, ideally about once a year.

Prevention and treatment

You can take steps to prevent high blood pressure by:

losing weight if you need to

reducing the amount of salt you eat

exercising regularly

eating a healthy diet

cutting back if you drink too much alcohol

stopping smoking

cutting down on caffeine

If your blood pressure is found to be high, it will need to be closely monitored until it is brought under control. Your doctor will usually suggest changes to your lifestyle and, sometimes, medication to achieve this. Find out more about how blood pressure is treated.

Symptoms of high blood pressure 

High blood pressure (hypertension) usually has no obvious symptoms and many people have it without knowing.

Untreated high blood pressure can lead to serious diseases, including stroke, heart disease and kidney failure.

The only way to know if you have high blood pressure is to have your blood pressure measured. All adults should get their blood pressure checked at least once every five years.

In some rare cases, where a person has very high blood pressure, they can experience symptoms, including:

a persistent headache

blurred or double vision


shortness of breath

Visit your GP as soon as possible if you find that you have any of these symptoms.


If you are pregnant, it's important to have your blood pressure checked on a regular basis, even if it isn't high.

Watching your blood pressure while you are pregnant reduces your risk of developing pregnancy-induced hypertension.

This can lead to a serious condition called pre-eclampsia where there is a problem with the placenta (the organ that links the baby’s blood supply to the mother’s).

Causes of high blood pressure 

In more than 90% of cases, the cause of high blood pressure (hypertension) is unknown but several factors can increase your risk of developing the condition.

Where there is no specific cause, high blood pressure is referred to by doctors as primary or essential hypertension.

Factors that can raise your risk of developing primary hypertension include:

age – the risk of developing high blood pressure increases as you get older

a family history of high blood pressure (the condition seems to run in families)

being of African or Caribbean origin

a high amount of salt in your food

a lack of exercise

being overweight or obese


drinking large amounts of alcohol

Known causes

About 10% of high blood pressure cases are the result of an underlying condition or cause. These cases are referred to as secondary hypertension.  

Common causes of secondary hypertension include:

kidney disease


narrowing of the arteries (large blood vessels) supplying the kidneys

hormonal conditions, such as Cushing's syndrome

conditions that affect the body’s tissue, such as lupus

oral contraceptive pill

painkillers known as nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen

recreational drugs, such as cocaine, amphetamines and crystal methamphetamine

herbal remedies, such as herbal supplements

Getting a blood pressure test 

High blood pressure (hypertension) often doesn't have any symptoms, so the only way to find out if you have it is to get your blood pressure checked.

Having this done is easy and could save your life.

Blood pressure testing is available in a variety of settings:

at your GP surgery by a GP, practice nurse, healthcare assistant or self-service machine

at a pharmacy

in some workplaces

at a health event

at home – you can check blood pressure yourself with a home testing kit

Healthy adults aged over 40 should have their blood pressure checked at least once every five years.

If you are at an increased risk of high blood pressure, you should have your blood pressure checked more often, ideally once a year.

You can ask for a blood pressure check – you don't have to wait to be offered one.

The test

Blood pressure can be measured using a manual or automatic device.

A cuff is placed around your arm and pumped up to restrict the blood flow. The pressure is then slowly released as your pulse is checked.

Hearing how your pulse beats after the cuff is released allows a measurement to be taken, giving a blood pressure reading.

Before having your blood pressure taken, you should rest for at least five minutes and empty your bladder.

To get an accurate blood pressure reading you should be sitting down with your back supported and legs uncrossed, and not talking when the reading is taken.

Confirming if you have high blood pressure

Having a raised blood pressure reading in one 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 will probably be given a blood pressure kit to take home, or be asked to wear a 24-hour monitor so you can monitor your blood pressure level throughout the day. This will confirm whether you have consistently high blood pressure.

You may also have blood and urine tests to check for conditions that are known to cause an increase in blood pressure, such as kidney disease.

Home testing

Portable machines that measure your blood pressure at home or on the move can be a useful way of getting a more convenient and accurate reading.

This is because some people become anxious in medical clinics, which can cause the blood pressure to rise. This is a condition called "white coat hypertension".

Home or portable blood pressure monitors may show that your blood pressure is in fact normal when you are relaxed.

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.

The British Hypertension Society (BHS) website has detailed information about clinically approved blood pressure monitors that are available to buy.

Understanding your blood pressure reading

Blood pressure is measured in millimetres of mercury (mmHg) and it is recorded as two figures:

systolic pressure (the top number) – the pressure of the blood when your heart pushes blood out

diastolic pressure (the bottom number) – the pressure of the blood when your heart rests in between beats, which reflects how strongly your arteries are resisting blood flow

If your GP says 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.

Ideally, your blood pressure reading should be below 120/80mmHg (for the lowest possible risk of disease). However, anything under 130/80mmHg is generally considered normal.

You are said to have high blood pressure if readings on separate occasions consistently show your blood pressure to be 140/90mmHg or higher.

If you have kidney disease, diabetes or a condition that affects your heart and circulation, your target blood pressure should be below 130/80mmHg.

Treating high blood pressure 

You can take effective steps to lower your blood pressure with changes to your lifestyle and by taking medication.

In all cases, you can benefit from making some simple lifestyle changes (outlined below). Whether you are also recommended to take medication will depend on your blood pressure level and your risk of developing a cardiovascular disease, such as a heart attack, stroke or kidney failure.

If your blood pressure is consistently above 140/90mmHg (or 135/85mmHg at home) but your risk of cardiovascular disease is low – you should be able to lower your blood pressure by making some changes to your lifestyle (see below). You may be offered yearly blood pressure assessments.

If your blood pressure is consistently above 140/90mmHg (or 135/85mmHg at home) but below 160/100mmHg – you will be offered medication to lower your blood pressure if you have existing or high risk of cardiovascular disease.

If your blood pressure is consistently above 160/100mmHg – you will be offered medication to lower your blood pressure.

Lifestyle changes

Below are some changes you could make to your lifestyle to reduce high blood pressure. Some of these will lower your blood pressure in a matter of weeks, others may take longer.

Cut your salt intake to less than 6g (0.2oz) a day.

Eat a healthy, low-fat, balanced diet, including plenty of fresh fruit and vegetables. Get tips on eating more healthily.

Be active: being physically active is one of the most important things you can do to prevent or control high blood pressure. Get tips on being more active.

Cut down on alcohol. Get tips on cutting down, download a drinks diary and keep track of your drinking.

Lose weight. Find out what your ideal weight is using the BMI healthy weight calculator.

Stop smoking. Smoking greatly increases your chances of getting heart and lung diseases. Get help quitting.

Drink less coffee, tea or other caffeine-rich drinks such as cola. Drinking more than four cups of coffee a day may increase your blood pressure.

You can take these steps today, regardless of whether or not you're taking blood pressure medication. You don’t need a doctor to prescribe lifestyle changes. 

The more healthy habits you adopt, the greater effect there is likely to be on your blood pressure.

In fact, some people find that, by sticking to a healthy lifestyle, they do not need to take any medicines at all. Find out more about preventing high blood pressure.


There is a wide range of blood pressure-lowering medicines to choose from and a combination is usually needed to treat high blood pressure most effectively and with the minimum side effects.

Taking such a combination of medication is nothing to worry about. The different types of medication work in different ways on your body. Read an FAQ page from Blood Pressure UK on Taking more than one medicine for high blood pressure.

The first medication you are offered will depend on your age.

If you are under 55 years old – you will usually be offered an ACE inhibitor or an angiotensin receptor blocker (ARB).

If you are aged 55 or older (or you're any age with African or Caribbean family origin) – you will usually be offered a calcium channel blocker.

In some cases, you may need to take blood pressure-lowering medication for the rest of your life. However, if your blood pressure levels stay under control for several years, your doctor might be able to reduce or stop your treatment.

It's really important you take your medications as directed. If you miss doses, the treatment will not work as effectively and you could lose protection against future illness. The medication won't necessarily make you feel any different, but this doesn't mean it's not working.

Here are some questions you might like to ask your doctor or nurse about your treatment.

You can also ask your pharmacist any questions about your medication, or approach them for advice on how to stick to your treatment plan.

Medications used to treat high blood pressure can have side effects but most people don't experience any. If they do, the large choice of blood pressure medicines means that they can often be resolved by changing treatments.

Let your GP or nurse know if you have any of the following common side effects while taking medication for high blood pressure:

feeling drowsy

pain around your kidney area (on the side of your lower back)

a dry cough

dizziness, faintness or lightheadedness

a skin rash

swelling of your feet

ACE inhibitors

Angiotensin-converting enzyme (ACE) inhibitors reduce blood pressure by relaxing your blood vessels. The most common side effect is a persistent dry cough. If side effects become particularly troublesome, a medication that works in a similar way to ACE inhibitors, known as an angiotensin-2 receptor antagonist (ARB), may be recommended.

ACE inhibitors can cause unpredictable effects if taken with other medications, including some over-the-counter ones. Check with your GP or pharmacist before taking anything in combination with this medication.


Calcium channel blockers

Calcium channel blockers keep calcium from entering the muscle cells of the heart and blood vessels. This widens your arteries (large blood vessels) and reduces your blood pressure.

Drinking grapefruit juice while taking some types of calcium blockerscan increase your risk of side effects. You can discuss the possible risks with your GP or pharmacist.


Sometimes known as water pills, diuretics work by flushing excess water and salt from the body through urine.



Beta-blockers work by making your heart beat more slowly and with less force, thereby reducing blood pressure.

Beta-blockers used to be a popular treatment for high blood pressure, but now they only tend to be used when other treatments have not worked. This is because beta-blockers are considered to be less effective than the other medications used to treat high blood pressure.

Complications of high blood pressure 

High blood pressure (hypertension) puts extra strain on your heart and blood vessels.

If untreated, over time this extra pressure can increase your risk of a heart attack, stroke, kidney disease and vascular dementia.

Cardiovascular disease

High blood pressure can cause many different diseases of the heart and blood vessels (medically known as cardiovascular diseases), including:

stroke – when the blood supply to part of the brain is cut off

heart attack – when the supply of blood to the heart is suddenly blocked

embolism – when a blood clot or air bubble blocks the flow of blood in a vessel

aneurysm – when a blood vessel wall bursts causing internal bleeding

vascular dementia – when blood flow to the brain is reduced, causing parts of the brain to become damaged

Kidney disease

High blood pressure can also damage the small blood vessels in your kidneys and stop them from working properly. Mild to moderate chronic kidney disease does not usually cause any symptoms.

Kidney disease may need treatment with a combination of medication and dietary changes.

More serious cases may require dialysis (a treatment where waste products are artificially removed from the body) or a kidney transplant.

Preventing high blood pressure 

Having high blood pressure can be prevented by eating healthily, maintaining a healthy weight, taking regular exercise, drinking alcohol in moderation and not smoking.


Cut down on the amount of salt in your food and eat plenty of fruit and vegetables. The eatwell plate highlights the different types of food that make up our diet, and shows the proportions we should eat them in to have a well balanced and healthy diet.

Salt raises your blood pressure. The more salt you eat, the higher your blood pressure. Aim to eat less than 6g (0.2oz) of salt a day, which is about a teaspoonful.

Eating a low-fat diet that includes lots of fibre (for example, wholegrain rice, bread and pasta) and plenty of fruit and vegetables helps lower blood pressure. Fruit and vegetables are full of vitamins, minerals and fibre that keep your body in good condition. Aim to eat five 80g portions of fruit and vegetables every day.


Regularly drinking alcohol above the recommended levels will raise your blood pressure over time. Staying within the recommended levels is the best way to reduce your risk of developing high blood pressure.

The recommends:

men should not regularly drink more than three to four units a day

women should not regularly drink more than two to three units a day

Alcohol is also high in calories, which will make you gain weight. This will also increase your blood pressure. 


Being overweight forces your heart to work harder to pump blood around your body, which can raise your blood pressure. Find out if you need to lose weight with the BMI healthy weight calculator.

If you do need to shed some weight, it is worth remembering that just losing a few pounds will make a big difference to your blood pressure and overall health. Get tips on losing weight safely.


Being active and taking regular exercise lowers blood pressure by keeping your heart and blood vessels in good condition. Regular exercise can also help you lose weight, which will also help lower your blood pressure.

Adults should do at least 150 minutes (2 hours and 30 minutes) of moderate-intensity aerobic activity (such as cycling or fast walking) every week. For it to count, the activity should make you feel warm and slightly out of breath. Someone who is overweight may only have to walk up a slope to get this feeling.

Physical activity can include anything from sport to walking and gardening. Get more ideas on being active.


Smoking doesn't directly cause high blood pressure but it puts you at much higher risk of a heart attack and stroke. Smoking, like high blood pressure, will cause your arteries to narrow. If you smoke and have high blood pressure, your arteries will narrow much more quickly and your risk of heart or lung disease in the future is dramatically increased. Get help to stop smoking.


Drinking more than four cups of coffee a day may increase your blood pressure. If you are a big fan of coffee, tea or other caffeine-rich drinks (such as cola and some energy drinks), consider cutting down.

It is fine to drink tea and coffee as part of a balanced diet but it is important that these drinks are not your only source of fluid. Find out if you are drinking enough fluids.