IT IS A MEASURE OF FORCE THAT BLOOD EXERTS ON THE ARTERIES

Blood pressure is a measure of the force blood exerts on the arteries as it is pumped around the body. To calculate blood pressure, two measurements are taken. The first is systolic. This is the pressure the blood exerts on the arteries when the heart beats. The second is diastolic. This is the pressure the blood exerts on the arteries when the heart relaxes between beats.

When blood pressure is measured, it is written down as two numbers, one over the other like a fraction, with systolic blood pressure on the top and diastolic pressure below, for example 120/80. This is said as '120 over 80'. Blood pressure is measured in units called millimetres of mercury, shortened to mmHg. 

IT CAN VARY THROUGHOUT THE DAY 

Your blood pressure can vary by large amounts depending on what you are doing. The lowest blood pressures occur when you are asleep or if you relax all your muscles. Standing up, exercising or anxiety all cause an increase in blood pressure.

'Normal' blood pressure also varies with age and state of health. As we get older our blood pressure rises. Pregnancy can also affect your blood pressure.

A normal blood pressure reading for a young adult falls into the range of 90/600 mmHg to 130/80 mmHg.

YOU CAN HAVE LOW BLOOD PRESSURE 

When the blood pressure is too low, the first organ it affects is the brain. This is because it is located at the top of the body and blood has to fight gravity to reach the brain. So, most people with low blood pressure feel light-headed or dizzy when they stand. Some people may even faint.

If you faint, you may fall to the floor bringing the brain to the level of the heart. This means the blood can flow to the brain without having to fight gravity and the blood flow to the brain increases, helping to protect it from injury.

Low blood pressure can also cause shortness of breath or chest pain due to an inadequate blood supply to the heart. If blood pressure becomes sufficiently low and stays low, all the organs can start to malfunction causing the body to go into shock.

Sometimes the body tries to compensate for low blood pressure and other symptoms may occur. Your skin, feet and hands may be cold and turn blue, and as the heart beats more quickly and more forcefully, you may feel palpitations.

If you think you may have low blood pressure, you should have it measured by a doctor, nurse or get a blood pressure monitor to measure it yourself. You should measure your blood pressure when you are standing, sitting and laying down. If when you stand there is a large fall in your blood pressure and you feel dizzy, you should seek further advice from your doctor.

YOU CAN SUFFER FROM HIGH BLOOD PRESSURE

High blood pressure is often referred to as hypertension. In most cases the cause is not known. Sometimes other conditions cause high blood pressure. This is known as 'secondary hypertension'.

Unlike other diseases, there are no signs or symptoms to tell you that you have high blood pressure. This is why hypertension is known as the 'silent killer'.

High blood pressure is quite common with about half of people over 65, and 1 in 4 middle age adults suffering from it. High blood pressure is considered to be anything over 140/90 mmHg.

You are more likely to have high blood pressure if you suffer from diabetes, have a family history of high blood pressure, are overweight, eat a lot of salt, don't exercise, or smoke and drink a lot of alcohol.

If you are diagnosed with high blood pressure, your doctor will perform some routine tests which will include:

• a urine test to check if you have protein or blood in your urine
• a blood test to check that your kidneys are working fine, and to check your cholesterol level and sugar level
• a heart tracing (ECG)

 The reason for these examinations and tests are:

• to rule out (or diagnose) a 'secondary' cause such as kidney disease
• to check if the high blood pressure has affected the heart
• to check for other 'risk factors' such as a high cholesterol level or diabetes

As high blood pressure usually has no symptoms, you should have regular checks at least every 3 years. If you are older, have had previous high readings or are diabetic, you should be checked by your doctor at least once a year.

HIGH BLOOD PRESSURE CAN LEAD TO OTHER DISEASES

You are at risk of having a heart attack, stroke, damage to the eyes, heart failure, angina or suffer from kidney damage if you have high blood pressure.

It is very important to keep a close monitor on your blood pressure. Also to help reduce your chances of developing it, you should eat a healthy diet with less salt, lose weight if necessary, take regular exercise, stop smoking and reduce your alcohol and caffeine intake.

CAN BE HELPED WITH MEDICATION

There are medicines to help with high blood pressure. These will be prescribed by your doctor.

• ACE inhibitors - these help to stop the production of a hormone called angiotensin II that makes the blood vessels narrow. They help the vessels expand, improving the blood flow.
• Angiotensin-II receptor antagonists - these work in a similar way to ACE inhibitors. But instead of stopping the production on angiotensin II, they block its action.
• Beta-blockers - these 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 - these 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 - these reduce muscle tension in the arteries, expanding them and creating more room for the blood flow. They also slightly relax the heart muscle so it beats more slowly, reducing blood pressure.
• Diuretics - they 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.
  

LIFESTYLE

1. Know your numbers, get your blood pressure checked every 90 days
2. Eat less salt (no more than 6g a day)
3. Eat more fruit and vegetables (at least 5 portions a day)
4. Try to eat 2-3 portions of oily fish per week
5. Be as active as you can (aim for 30 minutes, five times a week)
6. Drink alcohol in moderation
7. Keep to a healthy weight (lose weight if you have to)
8. Stop smoking