High blood pressure
Blood pressure is a measure of the pressure of blood flowing in the arteries. It's normal for blood pressure to increase when you exert yourself or when you feel stressed or anxious. But if your blood pressure is consistently higher than normal when you're at rest, you have high blood pressure, also known as hypertension.

Hypertension is a big problem - about half of people aged between 65 and 74 are affected, although the figures are a lot worse in some parts of the country than others.What is high blood pressure?

When your doctor takes your blood pressure, you'll be given two numbers, for example, 120/80 ('120 over 80'). The top figure - the systolic blood pressure - is a measure of the pressure when your heart is contracted and pumping blood. The bottom figure - the diastolic blood pressure - is the pressure when the heart is relaxed and filling with blood.

A diagnosis of hypertension is made if you have a blood pressure of 140/90 or higher. If your blood pressure is close to this, your doctor will probably want to monitor it regularly. If you suffer from diabetes, it is even more important that your blood pressure is lower than this - ideally less than 130/80.

Even if your blood pressure is high, you won't necessarily be given drug treatments to lower it.

People with hypertension have an increased risk of:
  • coronary heart disease, angina and heart attack
  • stroke
  • kidney damage
  • circulation problems in their legs, which could eventually lead to gangrene

If you smoke and have high blood pressure, you increase these risks. And the danger grows the longer you have the problem.
Types of hypertension
Most people with high blood pressure - 95% - have what's called primary or essential hypertension. This means that there's no single clear cause of it.

Although we know that some factors to do with lifestyle can contribute to hypertension, we don't really understand precisely the causes and why some people get it and others do not.

However, hypertension can run in families, and you are more likely to get it if close relatives have it.

But you are also more likely to develop hypertension if you:
  • are obese (very overweight)
  • drink a lot of alcohol
  • eat a lot of salt
  • are under a lot of stress
Secondary hypertension
You may be among the other 5% of people with high blood pressure who have what's known as secondary hypertension. This means your condition can be linked to a recognised cause - in fact, it may be a symptom of another underlying disease.

Secondary hypertension can be caused by:
  • kidney disease
  • adrenal gland disease
  • narrowing of the aorta

Secondary hypertension can also be cause by the contraceptive pill, or steroids, or if you are pregnant and suffering from pre-eclampsia.
Most people with hypertension don't have any symptoms. In fact, you may not even know you have a problem - most people are diagnosed when they have their blood pressure taken routinely as part of a medical examination. That's one good reason to have a regular check up with your doctor, especially if you're over 65.

You may have heard that people with high blood pressure experience headaches and dizziness - in most cases, that's not so. Only people with severe hypertension or a rapid rise in blood pressure are likely to experience warning headaches, blurred or impaired vision, fits or even pass out.

Before starting you on any course of treatment for hypertension, your doctor will give you a physical examination and monitor your blood pressure over a period of time to check that the high reading is an ongoing problem and not a one-off.

You may also need some tests, to see if your hypertension is having an effect on the rest of your body. These may include:
  • analysis of your urine (protein in your urine may be the first sign of a kidney problem)
  • a chest X-ray, to identify any cardiac enlargement
  • an ECG (electrocardiogram), to look for any heart strain
  • a blood test, to check the condition and working of your kidneys
If you have very severe hypertension, you may need to be admitted to hospital for initial treatment. But it's much more likely that you'll be able to deal with your hypertension at home.
Lifestyle changes
First, your doctor is likely to discuss lifestyle changes which might help. He or she might, for example, advise you to:
  • lose some weight
  • get some regular moderate exercise
  • cut down on salt and alcohol
  • stop smoking
You may then be prescribed drugs for your hypertension. If you are, you may need to stay on this medication for the rest of your life.

You may be given one or a combination of the following drugs.
  • diuretics, which increase the quantities of salt and water removed from your blood by your kidneys, and widen your arteries
  • beta-blockers, which reduce the work your heart has to do, by reducing your pulse rate, for example
  • ACE inhibitors or angiotensin 2 receptor antagonists, which block enzymes which constrict the blood vessels
  • calcium channel blockers or alpha blockers, which help widen your blood vessels

The drugs you are prescribed will depend on a number of factors, including their side effects, your other risk factors and if you have any other illnesses. For example, if you suffer from asthma, you should not be given a beta-blocker.

It may also take a time to find the best treatment for you, balancing the benefits against the side-effects.
Blood pressure monitors
You might also want to consider getting a blood pressure monitor to use yourself at home - discuss this option with your doctor, who should be able to help you choose a suitable one. If you do decide to buy one, go for a model that takes a measurement from your upper arm rather than your wrist or finger.
Further information

National Heart, Lung, and Blood Institute

American Heart Association
Healthwise (Health Information Resource Centre)
Tel : (852) 2849 2400
Fax : (852) 2849 2900
Email : info@healthwise.org.hk
Homepage : http://www.healthwise.org.hk/

This leaflet is for information only. For a detailed opinion or personal advice, please consult with your own doctor
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