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Systolic and Diastolic Blood Pressure

Systolic blood pressure refers to the pressure of blood in the artery when the heart contracts. It is the top (and higher) number in a blood pressure reading.

Diastolic blood pressure refers to the pressure of blood in the artery when the heart relaxes between beats. It is the bottom (and lower) number in a blood pressure reading.

For example, if a person's systolic pressure is 120 millimeters of mercury (mm Hg) and the diastolic pressure is 80 mm Hg, blood pressure is recorded as 120/80 and read as "120 over 80."

ByHealthwise Staff
Primary Medical ReviewerE. Gregory Thompson, MD - Internal Medicine
Specialist Medical ReviewerRobert A. Kloner, MD, PhD - Cardiology
Last RevisedApril 5, 2013

WebMD Medical Reference from Healthwise

Last Updated: April 05, 2013
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