How Is Blood Pressure Measured?

High blood pressure usually has no symptoms. The only way to tell whether you have high blood pressure is to perform a quick, painless measurement using a device called a sphygmomanometer. This instrument consists of a gauge and a rubber cuff that's placed around your arm or leg and inflated. 

The person taking your blood pressure wraps the cuff around your upper arm. Some cuffs go around the forearm or wrist, but often they're not as accurate.

Your doctor or nurse will use a stethoscope to listen for the appearance and disappearance of sound produced by the pulse in your elbow region. That's how the systolic and diastolic blood pressures are determined.

She’ll inflate the cuff to a pressure higher than your systolic blood pressure, and it will tighten around your arm. Then she'll release it. As the cuff deflates, the first sound she hears through the stethoscope is the systolic blood pressure. It sounds like a whooshing noise. The point where this noise goes away marks the diastolic blood pressure.

In a blood pressure reading, the systolic number always comes first, and then the diastolic number. A normal range is "120 over 80," written as 120/80. A high blood pressure reading would be 130/80 or higher. 

Blood Pressure Gauge Photo

 

WebMD Medical Reference Reviewed by James Beckerman, MD, FACC on September 06, 2019
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