The difference between the systolic and diastolic pressures is known as pulse pressure, while the average pressure during a cardiac cycle is known as mean arterial pressure. It is measured in millimeters of mercury ( mmHg) above the surrounding atmospheric pressure, or in kilopascals (kPa). Blood pressure is usually expressed in terms of the systolic pressure (maximum pressure during one heartbeat) over diastolic pressure (minimum pressure between two heartbeats) in the cardiac cycle. When used without qualification, the term 'blood pressure' refers to the pressure in a brachial artery, where it is most commonly measured. Most of this pressure results from the heart pumping blood through the circulatory system. A healthcare worker measuring blood pressure using a sphygmomanometer.īlood pressure ( BP) is the pressure of circulating blood against the walls of blood vessels.
