Blood pressure readings

If you have your blood pressure measured by either a nurse or your GP then you may wonder what those different readings mean. Which measurements indicate if you have normal or high blood pressure?

Blood pressure is measured in two numbers -systolic and diastolic. Systolic blood pressure is the top number and diastolic is the bottom number. It is also measured in millimetres of mercury (mmHg). So, a reading of 120/80 means a systolic blood pressure of 120 and a diastolic blood pressure of 80.

Systolic and diastolic are used to refer to the strength of pressure exerted on the artery walls as blood flows through. A change in any of these two numbers indicates either high or low blood pressure.

Systolic blood pressure

This is the highest amount of pressure exerted on the artery walls when your heart beats and circulates blood around your body.

Diastolic blood pressure

This is the lowest amount of pressure on the artery walls as your heart relaxes between beats. This a lower figure than systolic pressure.

These measurements determine your risk of having a heart attack or stroke.

Blood pressure measurements are as follows:

• 90/60 (or less): an indication of low blood pressure.
• More then 90/60 but less than 120/80: normal blood pressure
• More than 120/80 but less than 140/90: a bit higher than normal but still considered a healthy level.
• 140/90 or more: an indication of high blood pressure.

Use these as a rough guide only. Make sure you have your blood pressure checked by your GP or practice nurse.

What is defined as high blood pressure?

A reading of 90/60 is classed as low blood pressure although further tests will be carried out to determine this. Low blood pressure is discussed further in the next section.