Blood pressure (high) - hypertension

The heart pumps blood around the body through the blood vessels. Blood pressure is the amount of force the pumping blood exerts on the artery walls. High blood pressure (hypertension) means your blood is pumping with more force than normal through your arteries.

This added stress on the arteries can speed up the clogging of arteries with fatty plaques (atherosclerosis). Atherosclerosis contributes to many illnesses, such as heart attack and stroke. Other risk factors for atherosclerosis include cigarette smoking and high blood cholesterol.

Hypertension is a common disorder of the circulatory system. It affects around one in seven adults and becomes more common with age. Older people may notice a change in their blood pressure pattern as their arteries become more rigid (less elastic).

Most people with hypertension feel okay#

Hypertension usually produces no symptoms, so most people don’t realize they have it. Experts recommend that everyone have their blood pressure checked regularly, preferably yearly.

How blood pressure is controlled#

When the heart contracts, the blood inside the left ventricle is forced out into the aorta and arteries. The blood then enters small vessels with muscular walls, called arterioles. The tone in the muscular walls of the arterioles determines how relaxed or constricted they are. If the arterioles narrow, they resist flow.

Reduced blood flow is detected in the brain, the kidneys and elsewhere. Nerve reflexes are stimulated and hormones are produced. The heart is prompted to beat more forcefully so that blood pressure is maintained at a higher level, overcoming the restricted flow through the arterioles. Achieving good flow (now at high pressure) eases possible problems for the function of the brain and kidneys.

These adjustments occur normally. However, in some people the adjustments become fixed and high blood pressure persists. These people have developed hypertension.

Hypertension can be mild, moderate or severe. Your blood pressure is naturally higher when you are exerting yourself, such as during physical exercise. It is only a concern if your blood pressure is high when you are at rest, because this means your heart is overworked and your arteries have extra stress in their walls.

How blood pressure is measured#

Blood pressure readings combine two measurements:

• Systolic – the highest pressure against the arteries as the heart pumps. The normal systolic pressure is usually between 110 and 130mmHg.
• Diastolic – the pressure against the arteries as the heart relaxes and fills with blood. The normal diastolic pressure is usually between 70 and 80mmHg.

Blood pressure is measured using an instrument called a sphygmomanometer. An inflatable pressure bag is wrapped around the upper arm and connected to the sphygmomanometer.

The operator pumps up the bag with air until the circulation of the arm’s main artery is interrupted. The pressure in the bag is then slowly released until it equals the systolic pressure in the artery, indicated by blood once again moving through the vessel. This makes a ‘thumping’ sound, and the systolic pressure is read from the sphygmomanometer and recorded.

As the pressure in the bag falls further, the blood pressure in the arm’s main artery drops to equal the lowest pressure, which is the diastolic pressure. This is the pressure at which the thumping sound is no longer heard, and this figure is also recorded.

The operator may take several readings to get a true picture, because many people tend to ‘tense up’ during the procedure and nervous tension may temporarily boost the blood pressure. Electronic measuring and recording of both systolic and diastolic pressures is increasingly replacing manual and auditory blood pressure recording.

Why hypertension matters#

Hypertension usually does not produce any symptoms, because the body’s organs can resist high blood pressure for a long time. That’s why it’s important to have regular medical examinations to make sure your blood pressure isn’t creeping up as you grow older.

High blood pressure over a period of time can contribute to many illnesses, including:

• heart attack
• heart failure
• stroke
• kidney disease

What can cause high blood pressure#

An unhealthy lifestyle can contribute to hypertension. Some of the factors that can play a part include:

• hereditary factors
• obesity
• lack of exercise
• a diet high in salt
• heavy drinking
• cigarette smoking
• high levels of saturated fat in the diet
• high blood cholesterol
• changes in the arteries

Certain drugs can cause hypertension or make it harder to control. These may include:

• the combined contraceptive pill
• non-steroidal anti-inflammatories
• some nasal drops and sprays
• some cough medicines
• some eye drops
• appetite suppressants

If you think a medication may be affecting your blood pressure, check with your doctor or pharmacist for alternatives rather than stopping it on your own.

Blood pressure and ageing#

With advancing years, the arteries tend to become more rigid (less elastic). This may change a person’s blood pressure pattern, with a higher systolic pressure and a lower diastolic pressure. The higher systolic pressure is important because it can further accelerate the rigidity of the arteries. This state is referred to as ‘isolated systolic hypertension’. Although these changes are linked to ageing, this is not a normal state and may need medication to control the systolic pressure.

Making healthier choices#

Around two out of five people can successfully lower their blood pressure by making adjustments to their lifestyle. For example, a low-fat diet and giving up cigarette smoking will reduce the damaging effects of hypertension on the arteries. Some healthy lifestyle choices include:

• maintaining your weight within the healthy range
• eating a high-fiber, low-fat and low-salt diet
• giving up smoking
• limiting alcohol consumption
• exercising regularly

See your doctor before you start any new exercise program.

Antihypertensive medications#

In most cases, it is also necessary to take antihypertensive medication. Usually this medication is introduced at low doses, and the dose may be gradually increased if needed. A second or even a third drug may be added to achieve good blood pressure control. Not many people experience unpleasant side effects.

Any drug treatment for hypertension needs to be monitored carefully by your doctor. You should never alter the dose of your hypertension medication or stop taking it without consulting your doctor. Medications don’t cure the condition, and most people who need antihypertensive drugs will take them for the rest of their lives.

Key points#

• Other risk factors for atherosclerosis include cigarette smoking and high blood cholesterol.
• Hypertension usually produces no symptoms, so most people feel okay and don’t know they have it.
• Blood pressure combines systolic and diastolic measurements and is checked with a sphygmomanometer.
• Certain drugs can cause hypertension or make it harder to control.
• Lifestyle changes help, but most people also need long-term medication monitored by their doctor.

Where to get help and trusted information#

For evidence-based global health guidance, see Source: World Health Organization (WHO).