Blood Pressure Readings

Blood Pressure Readings

Systolic
The top number, which is also the higher of the two numbers, measures the pressure in the arteries when the heart beats (when the heart muscle contracts).

Diastolic
The bottom number, which is also the lower of the two numbers, measures the pressure in the arteries between heartbeats (when the heart muscle is resting between beats and refilling with blood).

The diastolic blood pressure number or the bottom number indicates the pressure in the arteries when the heart rests between beats.

A normal diastolic blood pressure number is less than 80.

A diastolic blood pressure between 80 and 89 indicates prehypertension.

A diastolic blood pressure number of 90 or higher is considered to be hypertension or high blood pressure.

This chart reflects blood pressure categories defined by the American Heart Association.

Blood Pressure
Category
Systolic
mm Hg (upper #)
Diastolic
mm Hg (lower #)
Normal less than 120 and less than 80
Prehypertension 120139 or 8089
High Blood Pressure
(Hypertension) Stage 1
140159 or 9099
High Blood Pressure
(Hypertension) Stage 2
160 or higher or 100 or higher
Hypertensive Crisis
(Emergency care needed)
Higher than 180 or Higher than 110

* Your doctor should evaluate unusually low blood pressure readings.

Blood-pressure-chart
Source: Understanding Blood Pressure Readings