What is blood pressure?
Blood pressure is a measure of the force of blood inside an artery.
If the pressure of blood is higher than normal on two or more occasions, you
may have high blood pressure (hypertension). The measurement is taken by
temporarily stopping the flow of blood in an artery, usually by inflating a
cuff around the upper arm, and then listening for the sound of the blood
beginning to flow through the artery again as air is released from the cuff. As
blood flows through the artery, it can be heard through a stethoscope placed on
the skin over the artery inside the elbow.
Blood pressure is recorded as two measurements.
- The reading on the gauge when blood flow is
first heard is called the systolic pressure. Systolic
pressure represents the peak blood pressure that occurs when the heart
contracts.
- The reading on the gauge when blood flow can no longer
be heard is the diastolic pressure. Diastolic pressure
represents the lowest blood pressure that occurs when the heart relaxes between
beats.
These two pressures are expressed in millimeters of mercury (mm
Hg). Systolic pressure, the higher of the two readings, is measured first.
Diastolic pressure is the lower reading. These blood pressure measurements are
recorded as systolic/diastolic. For example, if your systolic pressure is 120
mm Hg and your diastolic pressure is 80 mm Hg, your blood pressure is recorded
as 120/80 and read as "120 over 80."
Test Your Knowledge
People who have high blood pressure often don't know
it because it usually has no obvious symptoms.
- True
- False
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Why should I monitor my blood pressure at home?
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Monitoring your blood pressure at home