Measuring Blood Pressure

Measuring blood pressure involves using either a sphygmomanometer or a blood pressure machine. When measuring blood pressure, two numbers are recorded -- one appearing over the other as a fraction. The top number represents pressure when your heart is beating, while the bottom number measures pressure when your heart is resting. The unit used when measuring blood pressure is millimeters of mercury (mmHg).

 

Measuring Blood Pressure: An Introduction

Measuring blood pressure is quick and painless. Usually, measuring blood pressure involves using either a sphygmomanometer or a blood pressure machine. Blood pressure is measured in millimeters of mercury (mmHg) and recorded as two numbers -- systolic pressure "over" diastolic pressure. For example, the doctor or nurse might say "130 over 80" as a blood pressure reading. This is written as 130/80.
 
While both numbers in a blood pressure test are important, systolic blood pressure is especially important as people grow older.
 

Measuring Blood Pressure Using a Sphygmomanometer

When measuring blood pressure, your healthcare provider may use a familiar device with a long name.
 It is called a sphygmomanometer. This blood pressure testing device has a:
 
  • Valve
  • Cuff
  • Pump
  • Dial.
     
When a sphygmomanometer is used when measuring blood pressure, a fabric cuff is wrapped around the arm and then inflated. Then a stethoscope is used to listen to the sound of blood rushing back through the artery.
 
The healthcare provider then reads two numbers from a gauge attached to the cuff as air is released. The first number is read when a thumping sound is first heard (systolic pressure). The second number is when the thumping sound is no longer heard (diastolic pressure).
 
The two numbers that measure blood pressure are recorded as a fraction: one number on top and one on the bottom. For example, what many people consider normal blood pressure is read as 120/80. The number on top is your systolic pressure. It measures the pressure inside your blood vessels at the moment your heart beats. The number on the bottom is your diastolic pressure. It measures the pressure in your blood vessels between heartbeats, when your heart is resting.
 
(Measuring Blood Pressure Continued: Page 2)
Written by/reviewed by: Arthur Schoenstadt, MD
Last reviewed by: Arthur Schoenstadt, MD