What is hypertension?

Hypertension is defined as raised blood pressure, where systolic blood pressure is greater than or equal to 140 mmHg (millimetres of mercury) and/or diastolic blood pressure is greater than or equal to 90 mmHg.

It is classified by severity in the following stages:

• Stage 1 hypertension: clinic blood pressure between 140/90 and 159/99 mmHg and subsequent ambulatory blood pressure monitoring (ABPM)/home blood pressure monitoring (HBPM) average of 135/85 to 149/94 mmHg
• Stage 2 hypertension: clinic blood pressure at or above 160/100 mmHg but less than 180/120 mmHg and subsequent ABPM/HBPM average of 150/95 mmHg or higher
• Stage 3 (severe) hypertension: clinic systolic blood pressure of 180 mmHg or higher or clinic diastolic blood pressure of 120 mmHg or higher
• Accelerated (malignant) hypertension: a severe increase in blood pressure to 180/120 mmHg or higher with signs of retinal haemorrhage or swelling of the optic nerve.