The Full form of BP is Blood Pressure. BP is the pressure of circulating blood on the walls of blood vessels. This pressure is mostly due to work done by the heart by pumping blood through the circulatory system. Used without further specification, “blood pressure” usually refers to the pressure in large arteries of the systemic circulation. Blood pressure is usually expressed in terms of the systolic pressure (maximum during one heartbeat) over diastolic pressure (minimum in between two heartbeats) and is measured in millimeters of mercury (mmHg), above the surrounding atmospheric pressure. Blood pressure is one of the vital signs, along with respiratory rate, oxygen saturation, heart rate, and body temperature. Normal resting blood pressure in an adult is approximately 120 millimetres of mercury (16 kPa) systolic, and 80 millimetres of mercury (11 kPa) diastolic, abbreviated “120/80 mmHg”. Globally, the average blood pressure, age standardized, has remained about the same since 1975 to the present, at approx. 127/79 mmHg in men and 122/77 mmHg in women. In children, the normal ranges for blood pressure are lower than for adults and depend on height. Disorders of blood pressure control include low blood pressure, high blood pressure, and blood pressure that shows excessive or maladaptive fluctuation.