Understanding Your Blood Pressure

June 15, 2016

Blood pressure is typically recorded as two numbers: systolic and diastolic.

The top number, which is also the higher of the two numbers, measures the pressure of the blood on the walls of the arteries when your heart beats (when the heart muscle contracts and is exerting force). Typically more attention is given to the top number, because the top number is a better indicator of cardiovascular health.

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

What does the American Heart Association (the leading authority on Blood Pressure) recommend for a healthy blood pressure?

Blood Pressure
mm Hg (upper #)
mm Hg (lower #)
Normalless than 120andless than 80
Pre-hypertension120 – 139or80 – 89
High Blood Pressure
(Hypertension) Stage 1
140 – 159or90 – 99
High Blood Pressure
(Hypertension) Stage 2
160 or higheror100 or higher
Hypertensive Crisis
(Emergency care needed)
Higher than 180orHigher than 110

How is high/low blood pressure diagnosed?

If your blood pressure reading is higher than normal, your doctor may take several readings over a few weeks and/or have you monitor your blood pressure at home to get your average BP before diagnosing you with Hypertension or high blood pressure. One high reading does not always mean that you have high blood pressure, but if your BP readings remain high over time, your doctor may want you to begin treatment to lower your blood pressure, which may include adding a prescription and some lifestyle changes.

The process for diagnosing low blood pressure (hypotension) is the same.

Source: American Heart Association