When the heart contracts and forces blood into the arteries it creates a pressure called ‘blood pressure’. Every living person has a blood pressure, and it is this pressure that allows the blood to circulate around the body. Blood pressure varies throughout the day, going up during times of activity and going down when you are relaxed. Hypertension is the name given to the condition when the blood pressure is persistently high. The high pressure puts an excess strain on the heart, blood vessels, kidneys and other organs and increases the risk of developing heart attacks, strokes and kidney damage.
Blood pressure is measured usually using an instrument called a sphygmomanometer or by an electronic device. These instruments allow two readings to be taken of the pressure of the blood in the arteries – one when the heart contracts, called the systolic pressure and one when the heart relaxes, called the diastolic pressure. The pressure is measured in millimetres of mercury, written as mmHg (Hg is the chemical symbol for mercury), and is recorded as systolic pressure/diastolic pressure. Hypertension or high blood pressure is defined as a systolic pressure of 140 mmHg or greater, or a diastolic pressure of 90 mmHg or greater, which is written as 140/90.
As blood pressure is influenced by a number of factors, a diagnosis of hypertension should only be made after two readings have been taken on at least two separate occasions with the person sitting down and relaxed.
Hypertension is very common, affecting up to 1 in 4 of the adult population of the UK. A small number of people have what is called secondary hypertension, which means that there is an underlying cause of their high blood pressure. However, for most people there is no definite cause for their high blood pressure and doctors call this primary or essential hypertension. Some groups of people with certain lifestyles or hereditary factors are more likely to develop hypertension. These include:
- Those with a family history of high blood pressure
- Men – men are more likely to develop hypertension than women
- Ethnicity – black African, Caribbean and people from the Indian sub-continent are more likely to develop hypertension
- Those with an unhealthy lifestyle - if you are overweight, eat too much salt and not enough fruits and vegetables, take little exercise, drink too much alcohol and caffeine or smoke you are more likely to have high blood pressure
- Older people – blood pressure tends to rise as you get older
- Those who suffer from stress
Usually the only way to know if you have high blood pressure is to have it measured. Most people cannot tell if their blood pressure is high any other way. It is recommended that all adults should have their blood pressure measured at least every 5 years. Those with high normal values or with other risk factors such as diabetes or smoking should be measured at least annually.
Medicines
High blood pressure is not usually something that you can cure, but it can be treated. Everyone should make lifestyle changes such as stopping smoking, losing weight, cutting down the level of saturated fats in the diet, eating at least 5 portions of fruit and vegetables each day, taking regular exercise and limiting alcohol and caffeine intake. Women on oestrogen-containing oral contraceptives should consider changing to a progestogen-only contraceptive. Some people may be able get their blood pressure down by life style changes alone. Most people will also need to take blood pressure medication to lower blood pressure. The aim of treatment is to get your blood pressure down to 140/85 or even lower if you have other risk factors such as angina, diabetes or have had a previous heart attack. Once your blood pressure comes down, so does your risk of heart attacks and stroke.
Medications used to lower blood pressure are known as antihypertensives. There are a large number of different types of antihyptensives, all working in different ways within the body to lower blood pressure. Some of the most commonly used antihypertensives include ACE inhibitors (eg enalapril, lisinopril), A2 antagonists (eg losartan, valsartan), beta-blockers (eg propranolol, timolol), calcium antagonists (eg amlodipine, nifedipine) and diuretics (eg bendroflumethiazide). Your doctor will decide what kind of treatment is suitable for you by assessing your previous medical history and the presence of other risk factors. Often, two or more antihypetensives will be used together to improve the way that they lower blood pressure.
Many pharmacists now provide a blood pressure measuring service. You can simply call into your pharmacy to have your blood pressure checked if you are concerned about your blood pressure or simply want to know what it is. If you have risk factors for high blood pressure such as being overweight, you smoke and take very little exercise you should have your blood pressure checked at least once per year. If your pharmacist finds that your blood pressure is high, you will be advised to see your doctor.
Always tell your pharmacist if you are taking any antihypertensive medication. Many of these drugs have side effects and the pharmacist will be able to advise you on the correct way to take the medicine to help reduce these side effects. Your pharmacist also needs to know the type of antihypertensive medication you are taking to make sure that it does not interact with any products that may be sold to you without a prescription to treat other illnesses.
Your pharmacist will also be able to advise you on making lifestyle changes, for example giving up smoking, which will help lower your blood pressure.
If you have your blood pressure measured and it is above 140/90 then you should see your practice nurse or your doctor to have it checked again. If after several readings your high blood pressure is confirmed, your doctor will advise lifestyle changes such as diet and exercise, and may prescribe antihypertensive medication that is most suited to you.
Some patients decide not to take antihypertensive medication because they do not have any symptoms of high blood pressure. However, it is important that antihypertensive medication is taken all of the time. It is important not to ignore high blood pressure. The complications of uncontrolled high blood pressure cause more deaths and severe disability from heart attacks, stroke and kidney damage than any other disease. Never stop taking your antihypertensive medication suddenly as this could cause your blood pressure to rise to dangerously high levels.
