Doctors

About high blood pressure

Blood carrying oxygen and nutrients is pumped around your body by your heart. As a result of the pumping action of your heart and the size and flexibility of your arteries that carry blood, the blood is under pressure. This blood pressure is an essential part of the way your body works.

You can get high blood pressure if the walls of your larger arteries lose their elasticity and become rigid.

About three in 10 adults in the UK have high blood pressure. It's much more common in older people - seven out of 10 people over 70 have high blood pressure.

Symptoms

Most people with high blood pressure don't have any symptoms.

If you have very high blood pressure, or a rapid rise in blood pressure, you may have headaches, problems with your vision, fits or black-outs.

Complications

If you have high blood pressure, you have an increased risk of major illnesses including:

• cardiovascular disease such as angina (chest pain caused by reduced blood flow), stroke, heart attack, heart failure or atrial fibrillation (irregular heart beat)
• kidney damage
• damaged sight

Causes

Primary hypertension

More than nine in 10 people with high blood pressure have what is called primary or essential hypertension. This means that it has no single clear cause.

Although the exact cause of primary hypertension isn't fully understood, it's known that some factors to do with your lifestyle can contribute. These include:

• smoking
• obesity (being very overweight)
• drinking a lot of alcohol - especially if you binge drink
• lack of exercise
• your diet

If someone else in your family has high blood pressure, you also have a higher risk of developing it.

Secondary hypertension

Around one in 20 people with high blood pressure have secondary hypertension. This means your condition can be linked to a recognised cause such as:

• kidney disease
• endocrine disease (hormone disorders - a hormone is a regulatory chemical that occurs naturally in your body)
• a narrowing of the aorta (the largest artery leading from the heart) or the arteries leading to the kidneys

Secondary hypertension can also be caused by:

• steroid medicines
• the contraceptive pill
• pregnancy, which can cause pre-eclampsia - this can be serious and harm your baby

Diagnosis

As you might not have any symptoms, your GP may diagnose high blood pressure when you have your blood pressure taken as part of a medical examination. That's one good reason to have a regular check-up with your GP, especially if you're over 50.

Your GP or nurse will measure your blood pressure with a monitor called a sphygmomanometer. A cuff is placed around your upper arm and inflated to a certain level, then deflated slowly. A sensor in the cuff provides information about your blood pressure.

The result is expressed as two numbers, such as 120/80mmHg (one hundred and twenty over eighty millimetres of mercury).

• The first figure - the systolic blood pressure - is a measure of the pressure when your heart muscle is contracted and pumping blood. This is the maximum pressure in your blood system.
• The second figure - the diastolic blood pressure - is the pressure between heart beats when your heart is resting and filling with blood. This is the minimum pressure in your blood system.

In the UK, hypertension is defined as a consistently increased systolic blood pressure of 140 or over and/or a diastolic blood pressure of 90 or over. If your blood pressure is around this level, your GP will probably want to monitor it regularly.

If you have diabetes, your blood pressure should be lower than this - ideally less than 130/80.

Your GP may ask you to come back for repeat measurements over a number of weeks before suggesting that you have treatment. This is so he or she can check that the high reading is an ongoing problem and not a one-off.

You may also need some tests to see if hypertension is affecting the rest of your body. These may include:

• a urine test - protein in your urine may be the first sign of a kidney problem
• a blood test to check your cholesterol and blood sugar levels, as well as the condition of your kidneys
• an electrocardiogram (ECG) - a test that measures the electrical activity of your heart to see how well it's working

Monitoring

24-hour ambulatory monitoring

You may be given a 24-hour ambulatory monitoring to confirm your diagnosis. This will measure your blood pressure over 24 hours. A monitoring device will be strapped round your waist and attached to a cuff wrapped around your upper arm. The cuff will inflate and deflate automatically throughout the 24 hours and take recordings of your blood pressure.

Blood pressure monitors

You might consider getting a blood pressure monitor to use yourself at home - discuss this option with your GP. The Blood Pressure Association (see Further information) can provide you with a list of clinically validated blood pressure monitors.

It's important to take readings on different days - for example you shouldn't just measure your blood pressure when you feel stressed. Set days in the week to take the measurement so that you can get a consistent reading.

You should continue to have your blood pressure tested regularly by your GP even if you use a blood pressure monitor at home.

Treatment

You're likely to need long-term treatment for high blood pressure as it isn't curable.

You may not need much treatment if you only have slightly raised blood pressure, but regular monitoring is important.

If you have very high blood pressure, you may need to go to hospital for treatment. But it's much more likely that you will be cared for by your GP and/or a nurse.

Self-help

Your GP or nurse is likely to discuss lifestyle changes which might help. For example, he or she might advise you to:

• stop smoking
• change your diet to a low-fat, low-salt diet that includes fruit and vegetables
• cut down on alcohol
• cut down on coffee and high-caffeine drinks, such as cola
• take some regular, moderate exercise
• lose any excess weight

It may also help to try to reduce the stress in your life to prevent short-term rises in blood pressure - try relaxation techniques or meditation.

Medicines

If your blood pressure remains high, your GP may prescribe you one or more of the following antihypertensive medicines.

• ACE inhibitors (eg ramipril) or angiotensin II receptor antagonists (such as candesartan cilexetil eg Amias) - these relax and widen the walls of your blood vessels.
• Calcium-channel blockers (eg amlodipine) - these help to widen your blood vessels.
• Diuretics (eg bendroflumethiazide) - these increase the amount of water and salt removed from your blood by your kidneys. This lowers the volume of your blood which reduces blood pressure.
• Beta-blockers (eg atenolol) - these medicines reduce the work your heart has to do by reducing your pulse rate at rest and when you exercise.
• Alpha blockers (eg doxazosin) - these help to widen your blood vessels.

The medicines your GP prescribes will depend on a number of factors, including your age and ethnicity. It may take time to find the best treatment for you; one that balances benefits against any side-effects.

It's important to be committed to taking your medication every day even if you don't have any symptoms of high blood pressure.

Special considerations

Pregnancy

If you're pregnant your blood pressure will be monitored regularly whether you have hypertension or not. It's possible that you may develop high blood pressure during your pregnancy (pregnancy-induced hypertension) which can lead to serious problems (this is called pre-eclampsia).

If you have high blood pressure and think you may be, or are trying to become, pregnant it's important that you tell your GP. Certain medicines for treating high blood pressure aren't suitable for pregnant women.

Ethnic groups

If you're of African-Caribbean origin, you're at a higher risk of hypertension and you should visit your GP for regular monitoring.

You should also be monitored regularly if you're of South Asian origin because you have a higher risk of developing heart disease and diabetes.