Appropriate medical personnel can best determine how often blood pressure should be checked. Blood pressure is measured with a device called a sphygmomanometer. The arm should be bare or clothing should be flat to avoid constriction. The arm should be positioned so the cuff is at the level of the heart. An appropriate sized cuff is wrapped around the upper arm and inflated.
Pressure created by the cuff causes the blood flow to stop briefly in the arm.
As the air is released from the cuff, blood starts to flow through the artery. The person listening with the stethoscope is listening for sounds made as the blood flows through the artery. The first number recorded is the systolic pressure. This sound measures the pressure generated when the heart beats. The second number recorded is the diastolic, which measures the pressure between heartbeats.