What's Your Number?

Why it's important you keep track of your blood pressure.

What is blood pressure?

Blood pressure is the pressure of the blood in the arteries as the heart pumps it around the body.

How is blood pressure measured?

Blood pressure is usually measured by wrapping an inflatable pressure bag around the upper arm. The bag is connected to a pressure-measuring device. The entire instrument is called a “sphygmomanometer” (sfig-mo-mah-nom-eh-ter).

Blood pressure is recorded as two numbers, e.g. 120 over 80 (120/80)The higher number indicates the pressure in the arteries as the heart squeezes out blood during each beat. It is called the systolic blood pressure. The lower number indicates the pressure as the heart relaxes before the next beat. It is called the diastolic blood pressure. It is measured in millimetres of mercury.

It is best to measure blood pressure when you are relaxed and sitting or lying down.

Blood pressure varies

Blood pressure does not stay the same all the time. It is always changing to meet your body’s needs. If a reading is high, your doctor will measure your blood pressure again on several occasions to confirm the level. Your doctor may also recommend that you measure your blood pressure at home or have a recording with a monitoring device. This will be particularly so if your doctor believes that coming to the clinic makes your blood pressure rise. You can read more about measuring your blood pressure and monitoring devices in the Heart Foundation’s information sheet, Self-Measurement of Blood Pressure (available on the National Heart Foundation website).

What is high blood pressure?

There is no rule about what is high blood pressure, but the following figures are a useful guide:

Normal blood pressure: less than 120/80 (i.e. systolic less than 120 and diastolic less than 80). This is a guide only.

High – normal blood pressure: between 120/80 and 140/90.

High blood pressure: Equal to or more than 140/90. If the level is confirmed as equal to or more than 180/110 you have very high blood pressure.

Note: the word ‘hypertension’ is often used for high blood pressure. ‘Hypertension’ does not mean nervous tension.

Why does blood pressure matter?

If the blood pressure remains high it can cause serious problems like a heart attack, a stroke, heart failure or kidney disease. High blood pressure usually does not give warning signs. You can have high blood pressure and feel perfectly well. The only way to find out if your blood pressure is high is by having it checked regularly.

- Source: Source: Australian National Heart Foundation