Pumps work by generating pressure. Put simply, too much pressure puts a strain on the arteries and on the heart itself. This can cause an artery to rupture or the heart to fail under the strain – in the worst case stopping altogether.
Blood pressure depends on a combination of two factors:
- how forcefully the heart pumps blood around the body
- how narrowed or relaxed your arteries are.
Around 10 million people in the UK have high blood pressure – that's one in five of us.
What is normal blood pressure?
Blood pressure is measured using two numbers. An example of this could be 'the blood pressure is 120 over 80', which is written as '120/80mmHg'.- The first figure is the systolic blood pressure – the maximum pressure in the arteries when the heart contracts (beats) and pushes blood out into the body.
- The second figure is the diastolic blood pressure. This is the minimum pressure in the arteries between beats when the heart relaxes to fill with blood.
The systolic pressure is always listed first, then the diastolic pressure. A typical normal blood pressure reading would be 120/80 mmHg.
What's classed as high?
There is a natural tendency for blood pressure to rise with age due to the reduced elasticity of the arterial system. Age is therefore one of the factors that needs to be taken into account in deciding whether a person's blood pressure is too high.In general terms, people with a systolic blood pressure consistently above 140mmHg and/or a diastolic pressure over 85mmHg need treatment to lower their blood pressure.
People with slightly lower blood pressures (130 to140mmHg systolic or 80 to 85mmHg diastolic) may also need treatment if they have a high risk of developing cardiovascular disease, eg stroke or angina (chest pains).
What are the symptoms?
One of the big problems with high blood pressure is that it hardly ever causes symptoms.This means it may go unnoticed until it causes one of its later complications, such as a stroke or heart attack.
Despite the popularity of such ideas, nosebleeds and ruddy complexions are hardly ever caused by high blood pressure.
Severe hypertension can cause symptoms such as:
- headache
- sleepiness
- confusion
- coma.
What complications are caused by high blood pressure?
- Atherosclerosis: narrowing of the arteries.
- Stroke: haemorrhage or blood clot in the brain.
- Aneurysm: dangerous expansion of the main artery either in the chest or the abdomen, which becomes weakened and may rupture.
- Heart attack.
- Heart failure: reduced pumping ability.
- Kidney failure.
- Eye damage.
What causes hypertension?
For more than 95 per cent of people with high blood pressure, the cause is unknown. This is called 'primary' or 'essential hypertension'.In the remaining 5 per cent or so, there is an underlying cause. This is called 'secondary hypertension'.
Some of the main causes for secondary hypertension are:
- chronic kidney diseases
- diseases in the arteries supplying the kidneys
- chronic alcohol abuse
- hormonal disturbances
- endocrine tumours.
What factors increase the risk of hypertension?
Anyone can suffer from high blood pressure, but certain factors can seriously aggravate hypertension and increase the risk of complications:- a tendency in the family to suffer hypertension
- obesity
- smoking
- diabetes Type 1 or Type 2
- kidney diseases
- high alcohol intake
- excessive salt intake
- lack of exercise
- certain medicines, such as steroids.
What can I do?
Every adult near or past middle age should ‘know their numbers’ – ie your height, weight, blood pressure and cholesterol levels.You should also have regular blood pressure tests if there is a family tendency for hypertension. This way, treatment can be started before any complications arise.
Change your lifestyle:
- stop smoking
- lose weight
- exercise regularly – as a minimum, 20 minute sessions, three times a week, sufficiently intense to induce some breathlessness
- cut down on alcohol – aiming for less than 21 units a week for men, 14 units a week for women
- eat a varied diet
- avoid all salt in food
- reduce stress by trying different relaxation techniques or by avoiding stressful situations.
If your blood pressure requires medical treatment, you will probably have to take medicine on a regular basis.
If so, never stop taking it without consulting your GP, even if you feel fine. Hypertension can lead to serious complications if left untreated.
What can your doctor do?
- Pinpoint risk factors and help you change your lifestyle to reduce blood pressure.
- Offer medication for the reduction of blood pressure and arrange regular monitoring. Sometimes blood pressure control is not straightforward. Many people require more than one drug on a regular basis to get their blood pressure under good control.
- Your GP may wish to seek the advice of an expert in hypertension if your blood pressure seems particularly difficult to control.
What are the treatment targets?
Diabetes considerably increases the risk of cardiovascular disease if hypertension is also present, so the targets for blood pressure control in diabetes are tighter.For people who don't have diabetes, the treatment goals for blood pressure for are:
- systolic pressure of less than 140mmHg
- diastolic pressure of less than 85mmHg.
- systolic pressure of less than 130mmHg
- diastolic pressure of less than 80mmHg.
Which medicines are used to treat hypertension?
- ACE inhibitors stop the production of a hormone called angiotensin II that makes the blood vessels narrow. As a result, the vessels expand, improving blood flow. Tension in the circulation is also lowered by the kidneys filtering more fluid from the blood vessels into urine. This also helps reduce blood pressure. If your blood pressure is not easily controlled on simple medication, your doctor will probably use a medicine of this type.
- Angiotensin-II receptor antagonists work in a similar way to ACE inhibitors. But instead of stopping the production of angiotensin II, they block its action. This allows the blood vessels to expand, improving blood flow and reducing blood pressure.
- Beta-blockers block the effect of the hormone adrenaline and the sympathetic nervous system on the body. This relaxes the heart so that it beats more slowly, lowering the blood pressure.
- Alpha-blockers cause the blood vessels to relax and widen. Combining them with beta-blockers has a greater effect on the resistance in the circulation.
- Calcium-channel blockers reduce muscle tension in the arteries, expanding them and creating more room for the blood flow. In addition, they slightly relax the heart muscle so it beats more slowly, reducing blood pressure.
- Diuretics help the body get rid of excess salt and fluids via the kidneys. In certain cases, they relax blood vessels, reducing the strain on your circulation.
- Indapamide (eg Natrilix) is a mildly diuretic preparation that also relaxes the peripheral arteries.
- Hydralazine (eg Apresoline) relaxes the vascular walls in the peripheral arteries thereby reducing the blood pressure.
- Methyldopa (eg Aldomet) stimulates the alpha receptors in the brain that relax the blood vessels, causing the blood pressure to drop.
- Moxonidine (eg Physiotens) is another medicine that acts on receptors in the involuntary part of the brain, causing blood pressure to decrease.
- Minoxidil (Loniten) relaxes the small arteries so that blood pressure drops. It must be used in combination with other hypertension medicines.
Cholesterol
An important factor in determining the danger of high blood pressure is your cholesterol – a high cholesterol increases the sensitivity of the arteries to high blood pressure and makes them more likely to be damaged.This means that when treating blood pressure, it's crucial to know what the cholesterol is – and if it is raised, to bring it down.
While diet, exercise, ideal weight and regular exercise are all important in reducing cholesterol, most people with high blood pressure and normal or high cholesterol also need a cholesterol lowering drug, such as a statin.
In the long term
By treating hypertension well, complications can be avoided and average life expectancy will remain almost normal.Without treatment, life expectancy may well be reduced due to the risk of developing complications such as heart failure or stroke.
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