ABOUT BLOOD PRESSURE
What is blood pressure?
When the heart pumps blood around the body, the blood exerts pressure on the walls of the blood vessels. This is known as blood pressure.
•Blood pressure is different in different parts of the body and depends on the pulse, how elastic the blood vessels are and how thick the blood is.
•The pressure that can be measured when the heart pumps out into the body is known as systolic blood pressure. The pressure that can be measured when blood runs back from the body is known as diastolic blood pressure.
•The two types of blood pressure are usually given together, with the systolic blood pressure always given first. If blood pressure is given as "120/70" (expressed as "120 over 70"), this means that the systolic blood pressure is 120, and the diastolic 70.
•The measurement unit for blood pressure is mmHg (millimetres of mercury).
Why does blood pressure vary?
Blood pressure varies throughout the day and over a person’s life. Many different factors affect your blood pressure, something you should be aware of when taking your blood pressure. For instance, be aware of the following:
•Blood pressure is higher during the day than at night.
•Blood pressure increases slightly after you have just eaten. A lot of salt in food can also increase blood pressure.
•Light exercise (e.g. walking and jogging) causes the systolic blood pressure to rise slightly, while hard exercise
will cause it to rise dramatically. However, it will fall again when the body relaxes. A lack of exercise raises blood pressure permanently.
•Blood pressure can increase if you are excited, stressed or tense.
•Sudden climatic changes can cause blood pressure to rise.
•The systolic pressure increases with age.
•Women have a greater risk of increased blood pressure after the menopause.
•Insufficient sleep, smoking, obesity, alcohol and certain illnesses cause blood pressure to rise.
•Bathing and toilet visits may cause blood pressure to rise.
When is my blood pressure too high or too low?
High blood pressure is also called hypertension. Low blood pressure is also called hypotension. The diagram below shows when your blood pressure is too high or too low.
Range | Systolic | Diastolic |
Hypertension | > 140 mmHg | > 90 mmHg |
High normal | ||
Normal | ||
Hypotension | < 90 mmHg | < 50 mmHg |
Why should I measure my blood pressure?
Blood pressure naturally increases as you get older, but high blood pressure can also be the first sign of illness, being overweight or of the arteries beginning to stiffen, which increases the risk of blood clots, among other things. It is therefore a good idea to keep an eye on your blood pressure and consult a doctor if it seems unusually high or low.
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