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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."

Author Jeannette Curtis
Author Caroline Rea, RN, BS, MS
Editor Kathleen M. Ariss, MS
Editor Susan Van Houten, RN, BSN, MBA
Associate Editor Tracy Landauer
Associate Editor Pat Truman
Primary Medical Reviewer Patrice Burgess, MD
- Family Medicine
Primary Medical Reviewer Adam Husney, MD
- Family Medicine
Primary Medical Reviewer Kathleen Romito, MD
- Family Medicine
Last Updated May 25, 2007

WebMD Medical Reference from Healthwise

Last Updated: May 25, 2007
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