The blood pressure range of normal adults in quiet state is relatively stable, with systolic blood pressure of 90 ~ 139mmhg, diastolic blood pressure of 60 ~ 89mmhg and pulse pressure of 30 ~ 40mmhg. The normal value of blood pressure in children of different ages is systolic blood pressure (mmHg) = age × 2+80； Diastolic blood pressure = systolic blood pressure × 2/3。

The following shall be classified as abnormal blood pressure--

Hypertension: systolic blood pressure ≥ 140mmHg and / or diastolic blood pressure ≥ 90mmHg in adults over 18 years old without antihypertensive drugs.

Hypotension: the blood pressure is lower than 90 / 60mmhg.