What do the numbers mean?

Digital blood pressure readings have two numbers – systolic blood pressure and diastolic blood pressure. The top number is your systolic blood pressure (the highest pressure when your heart beats and pushes blood around your body), and the bottom number is your diastolic blood pressure (the lowest pressure between heart beats). A blood pressure reading is usually these two numbers over each other – like 120/80.

High blood pressure


High blood pressure (hypertension) occurs when your blood pressure is consistently more than 140 over 90. This higher pressure puts more strain on your heart and blood vessels, increasing your risk of heart attacks and stroke. High blood pressure can also lead to heart and kidney disease, and is also closely linked to some forms of dementia.

High blood pressure usually has no signs or symptoms, so the only way to know is to have your blood pressure measured. Occasionally people with very high blood pressure may experience headaches, so it’s best to consult your GP if you are worried about symptoms.

We don’t know exactly what causes high blood pressure, only that some aspects of your lifestyle – eating too much salt, not being active enough, being overweight - can affect your chance of developing it.

Low blood pressure


Low blood pressure (hypotension) occurs when you have a reading that is consistently 90 over 60 or lower.  In general this is a good thing, as it decreases your risk of heart attacks and strokes, but in some cases low blood pressure can cause other problems. It’s best to speak to your doctor or nurse in any case if you are concerned.

Usually low blood pressure is not a cause for concern, but if you find that your blood pressure is suddenly much lower than normal you should consult your GP just in case.

blood pressure readings chart