Blood pressure - the definition

Put simply, blood pressure is the pressure of blood in your arteries  - the tubes that carry your blood from your heart to your brain and the rest of your body. You need a certain amount of pressure to get the blood round your body.
The pressure of blood flowing through your arteries varies due to your heart pumping. When your heart pumps blood out of your heart into your arteries, the pressure in your arteries will be at its highest. When your heart is relaxing before it pumps again the pressure in your arteries will be at its lowest.

What do the numbers mean?

When we do get our blood pressure tested, the numbers our doctor or nurse gives us when taking our blood pressure can mean little to us.
Every blood pressure reading consists of two numbers or levels. They are shown as one number on top of the other and measured in mmHg, which means millimetres of mercury.  If your reading is 120/80mmHg, you might hear your doctor or nurse saying your blood pressure is "120 over 80".

• The first (or top) number represents the highest level your blood pressure reaches when your heart beats and pumps blood into your arteries - your systolic blood pressure. An example might be 130mmHg.
  
• The second (or bottom) numbert represents the lowest level your blood pressure reaches as your heart relaxes between beats - your diastolic blood pressure. An example might be 75mmHg.

You should have your blood pressure measured so that you know what your target is. Normally your target is to have a blood pressure below 140/85mmHg.
However, if you have heart or circulatory disease, including being told you have coronary heart disease, angina, heart attack or stroke, have diabetes or kidney disease, then your blood pressure should be below 130/80mmHg.

What is high blood pressure?

High blood pressure – or hypertension – means that your blood pressure is constantly higher than the levels above. High blood pressure is not usually something that you can feel or notice, but over time your heart may become abnormally large and beat less effectively.

Having high blood pressure increases your chance of having a heart attack or stroke. If left untreated it puts extra strain on your heart muscle which can lead to heart failure.

There isn’t always an explanation for the cause of high blood pressure, but these can play a part:

• not doing enough physical activity
• being overweight or obese
• too much salt in your diet
• drinking too much alcohol
• not eating enough fruit and vegetables or,
• having a family history of high blood pressure.

Even if you don't have high blood pressure, making simple lifestyle changes may help prevent you developing it in the future.

What can I do to reduce my blood pressure?

If your doctor or nurse says you have high blood pressure, he/she is likely to encourage you to make some lifestyle changes to help reduce it. This may include increasing your physical activity, losing weight, reducing the salt in your diet, cutting down on alcohol and eating a balanced, healthy diet.
If your blood pressure is very high or these lifestyle changes do not reduce it enough, your doctor is likely to prescribe you medication to control it and to reduce your risk of having a heart attack or stroke.