Blood pressure is a measure of the force exerted on the walls of the arteries from blood being pushed through them by the heart. According to the Texas Heart Institute, it is important to have blood pressure checked regularly because high blood pressure does not produce symptoms in most people.
Measurement
Blood pressure is measured with a special instrument called a sphygmomanometer. A rubber cuff is secured around the upper arm and inflated. According to the American Heart Association, the inflated cuff compresses a large artery in the arm which stops blood flow. As the cuff is deflated, the healthcare professional listens with a stethoscope and records two readings.
Readings
The two numbers recorded represent the systolic pressure, the force of moving blood when the heart beats, and the diastolic pressure, the force of moving blood between heartbeats. These pressures are measured in millimeters of mercury, recorded as "mm Hg." These units signify how high the pressure would raise a column of mercury.
Ideal Blood Pressure
An accurate determination of blood pressure is based on two readings taken at rest. According to MedlinePlus, the ideal blood pressure reading is a systolic reading less than 120 and diastolic less than 80, or less than 120/80 mm Hg.
