High blood pressure

Regular blood pressure checks are recommended

High blood pressure, or hypertension, increases the risk of heart attacks, strokes, kidney failure, damage to the eyes, congestive heart failure and atherosclerosis.

It causes the heart to work harder than normal putting both the heart and arteries at greater risk of damage.

There are no external signs of high blood pressure, leading many people to have it for years without noticing.

When combined with obesity, smoking, high blood cholesterol levels or diabetes, the risk of heart attack or stroke is several times higher.

If high blood pressure isn't treated, the heart may have to work harder and harder to pump enough blood and oxygen to the body's organs and tissues to meet their needs.

Causes

Diabetes and diet, particularly salt, are key causes of hypertension. The risk of high blood pressure for black people is around three times that faced by white people.

Use of oestrogen-based contraceptive pills and hormone replacement therapy has been implicated as a cause.

When it is forced to work harder than normal for an extended time, the heart enlarges and weakens. While a slightly enlarged heart may work well, one that is significantly enlarged has a hard time meeting the demands put on it.

Arteries also suffer the effects of high blood pressure, becoming scarred, hardened and less elastic.

Though this hardening of the arteries often occurs with age, high blood pressure accelerates the process.

The hardened or narrowed arteries are unable to supply the amount of blood the body's organs need, preventing them working effectively.

Blood clot

Another risk is that a blood clot may lodge in an artery narrowed by atherosclerosis, blocking blood supply.

HIGH BLOOD PRESSURE DEFINITION Blood pressure at or above 140mm Hg when the heart is contracting - systolic Blood pressure at or above 90mm Hg when the heart is relaxing - diastolic

Hypertension exists where the pressure at which blood is pushing against blood vessel walls is consistently above average.

It is measured in millimetres of mercury (mm Hg) and is defined in an adult as a blood pressure equal to or above 140mm Hg when the heart is contracting - systolic - and 90mm Hg when the heart is relaxing - diastolic.

Untreated high blood pressure can cause the heart to become abnormally large and less efficient - ventricular hypertrophy, causing heart failure and increased risk of heart attack.

In 90 to 95% of cases, the cause is unknown.

In the remaining cases, high blood pressure is a symptom of a recognisable underlying problem such as a kidney abnormality, tumour of the adrenal gland or congenital defect of the aorta.

When the root cause is corrected, blood pressure usually returns to normal. This type of high blood pressure is called secondary hypertension.

The only way to find out if you have high blood pressure is to have your blood pressure checked. A doctor or other qualified health professional should check a patient's blood pressure at least once every two years.

The condition can be effectively controlled using drugs - usually ACE inhibitors or beta-blockers.