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What is high blood pressure?


If your blood pushes against your blood vessel walls with too much force, it puts a strain on your heart and blood vessels.

This is high blood pressure (hypertension).

When your heart beats, it pumps blood around your body to give it the energy and oxygen it needs. As the blood moves, it pushes against the sides of the blood vessels. The strength of this pushing is your blood pressure.

If your blood pressure is too high, it puts extra strain on your heart and blood vessels. This is called high blood pressure, or hypertension. Over time it can lead to a number of health problems including heart attacks, stroke, kidney disease and some forms of dementia. The good news is there are lots of things you can do to 
lower it.

High blood pressure is very common, about a third of adults in the UK have it, but many aren’t aware of it. It doesn’t usually have any symptoms so the only way to know you have it is to have a blood pressure check.


How is blood pressure measured?

Blood pressure is measured in millimetres of mercury (mmHg) using a simple machine. When you have it measured it will be written as two numbers, a top number and a bottom number. For example, if your reading is 120/80mmHg, your blood pressure is 120 over 80.

Find out more about what the numbers mean and if yours is in the healthy range.


What should your blood pressure be?

Ideally, we should all have a blood pressure reading between 90/60mmHg and 120/80mmHg.

Most people in the UK have blood pressures higher than the ideal, but below the usual cut-off for diagnosing high blood pressure – somewhere between 120/80mmHg and 140/90mmHg. If you’re in this range, you could develop high blood pressure in the future. Taking steps to lower your blood pressure will keep your risk of health problems down.


What is a high blood pressure reading?

You will probably be diagnosed with high blood pressure (hypertension) if your readings are consistently 140/90mmHg or higher over a number of weeks. This is the cut-off point many GPs use for diagnosing high blood pressure.

You might also have high blood pressure if just one of the numbers is higher than it should be – so if the top number is over 140mmHg or the bottom number is over 90mmHg.

A single high reading doesn’t necessarily mean you have high blood pressure, as many things can affect your blood pressure throughout the day and it could just be a one-off. If you have a high reading, your doctor or nurse will want to see if it stays high over time before diagnosing high blood pressure.


What are the symptoms of high blood pressure?

Blood pressure isn’t usually something that you feel or notice. High blood pressure usually has no symptoms, so the first sign of it can sometimes be a heart attack or stroke. That’s why it’s called the silent killer. The only way to find out if you have high blood pressure is to have a blood pressure check

Occasionally, people with very high blood pressure have symptoms including:

  • headaches
  • blood shot eyes
  • feeling sick or generally unwell

Visit your GP if you have any symptoms you’re worried about.


Who should have a blood pressure check?

All adults should have their blood pressure checked. Blood pressure becomes more common with age, so if you’re over 40 you should have a blood pressure check at least every five years. It’s a good idea to have a blood pressure check if you are younger as well, especially if you are carrying extra weight or have other health problems.


Where can you get a blood pressure check?

You can have your blood pressure checked at your GP surgery, in some pharmacies, in some work places or as part of an NHS health check. It’s quick, easy, free and painless. See where you can have it checked.

You can also measure your blood pressure at home using a home monitor.


What causes high blood pressure?

For many people, there may be no one single cause of their high blood pressure, but lifestyle often plays an important role. Being overweight, eating too much salt, which is often hidden in packaged foods, not being active, drinking too much alcohol and smoking can all raise your blood pressure.

Your age, ethnic background, and even your genes could play a role, and sometimes high blood pressure is caused by another health problem such as a kidney problem.


What are the types of high blood pressure?

If you have high blood pressure with no known single cause, this is called essential hypertension or primary hypertension. Most people have this type of hypertension. If you have high blood pressure which is caused by another health problem, this is known as secondary hypertension, and treating the cause should bring your blood pressure back down to normal.


Why is high blood pressure a problem?

High blood pressure puts an extra strain on your heart and blood vessels, which can damage them and make them weaker. Over time, this can lead to health problems including heart attacks, heart failure, stroke, some forms of dementia, kidney disease and peripheral arterial disease. 

If you have other health problems as well as high blood pressure, such as diabetes or high cholesterol, this makes serious health problems in the future more likely, making it more important to take steps to lower your blood pressure.

Keep your blood pressure under control

The higher your blood pressure, the higher your risk of health problems, and lowering it is one of the best things you can do for your health. Even a small change can make a big difference – lowering the top number by 10mmHg lowers the risk of a heart attack or stroke by 20%.

Some people have blood pressure below the healthy range. This is known as low blood pressure, but is normally nothing to worry about. The video below shows how to keep a healthy blood pressure.

You can start taking steps today to lower your blood pressure and keep it in check. Read more about the changes you can make to your diet and lifestyle, and the medications that are available if you need them.

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