WHAT IS HYPERTENSION?

1. What is raised blood pressure (hypertension)?

Hypertension, also known as high or raised blood pressure, is a condition in which the blood vessels have persistently raised pressure. Blood is carried from the heart to all parts of the body in the vessels. Each time the heart beats, it pumps blood into the vessels. Blood pressure is created by the force of blood pushing against the walls of blood vessels (arteries) as it is pumped by the heart. The higher the pressure the harder the heart has to pump.

Normal adult blood pressure is defined as a blood pressure of 120 mm Hg when the heart beats (systolic) and a blood pressure of 80 mm Hg when the heart relaxes (diastolic). When systolic blood pressure is equal to or above 140 mm Hg and/or a diastolic blood pressure equal to or above 90 mm Hg the blood pressure is considered to be raised or high.

Sometimes hypertension causes symptoms such as headache, shortness of breath, dizziness, chest pain, palpitations of the heart and nose bleeds. However, most people with hypertension have no symptoms at all.

2. Why is raised blood pressure dangerous?

The higher the blood pressure, the higher the risk of damage to the heart and blood vessels in major organs such as the brain and kidneys.

If left uncontrolled, hypertension can lead to a heart attack, an enlargement of the heart and eventually heart failure. Blood vessels may develop bulges (aneurysms) and weak spots that make them more likely to clog and burst. The pressure in the blood vessels can cause blood to leak out into the brain and cause a stroke. Hypertension can also lead to kidney failure, blindness, and cognitive impairment.

The health consequences of hypertension can be compounded by other factors that increase the odds of heart attack, stroke and kidney failure. These factors include tobacco use, unhealthy diet, harmful use of alcohol, lack of physical activity, and exposure to persistent stress as well as obesity, high cholesterol and diabetes mellitus.

3. How can raised blood pressure be prevented and treated?

All adults should have their blood pressure checked. If blood pressure is high, they need the advice of a health worker.

For some people, lifestyle changes are sufficient to control blood pressure such as stopping tobacco use, eating healthily, exercising regularly and avoiding the harmful use of alcohol. Reduction in salt intake can help. For others, these changes are insufficient and they need prescription medication to control blood pressure.

Adults can support treatment by adhering to the prescribed medication, by monitoring their health.

People with high blood pressure who also have high blood sugar or elevated blood cholesterol face even higher risk of heart attacks and stroke. Therefore it is important that regular checks for blood sugar, blood cholesterol and urine albumin take place.

Everyone can take five concrete steps to minimize the odds of developing high blood pressure and its adverse consequences.

• Healthy diet:
• promoting a healthy lifestyle with emphasis on proper nutrition for infants and young people;
• reducing salt intake to less than 5 g of salt per day (just under a teaspoon);
• eating five servings of fruit and vegetables a day;
• reducing saturated and total fat intake.
• Avoiding harmful use of alcohol i.e. limit intake to no more than one standard drink a day
• Physical activity:
• regular physical activity and promotion of physical activity for children and young people (at least 30 minutes a day).
• maintaining a normal weight: every 5 kg of excess weight lost can reduce systolic blood pressure by 2 to 10 points.
• Stopping tobacco use and exposure to tobacco products
• Managing stress in healthy way such as through meditation, appropriate physical exercise, and positive social contact.

4. How common is raised blood pressure?

More than one in three adults worldwide have raised blood pressure – a condition that causes around half of all deaths from stroke and heart disease. It is considered directly responsible for 7.5 million deaths in 2004 – almost 13% of all global deaths.

In nearly all high-income countries, widespread diagnosis and treatment with low-cost medication have led to a dramatic drop in mean blood pressure across populations – and this has contributed to a reduction in deaths from heart disease.

For example in 1980, almost 40% of adults in the WHO European Region and 31% of adults in the WHO Region of the Americas had high blood pressure. By 2008, this had dropped to below 30% and 23% respectively.

In contrast, in the WHO African region, more than 40% (and up to 50%) of adults in many countries are estimated to have high blood pressure and this proportion is increasing.

Many people with high blood pressure in developing countries remain undiagnosed, and so miss out on treatment that could significantly reduce their risk of death and disability from heart disease and stroke.

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¹ Blood pressure is measured in millimeters of mercury (mm Hg).

SOURCE: WHO.int