It occurs when the heart relaxes and fills with blood.Įach time the heart beats, it pumps blood into the arteries, resulting in the highest blood pressure, the systolic pressure, as the heart contracts, and the lowest blood pressure, the diastolic pressure, as the heart relaxes.īoth the systolic and diastolic pressures are recorded as 'mm Hg' (millimeters of mercury). The lower number, or diastolic pressure, refers to the lowest pressure inside the artery. It occurs when the heart contracts and pumps blood into the body. The higher number, or systolic pressure, refers to the highest pressure inside the artery. Two numbers are recorded when measuring blood pressure: High Blood Pressure in Children and Adolescents What is blood pressure?īlood pressure, measured with a blood pressure cuff and stethoscope by a nurse or other health care provider, is the force of the blood pushing against the artery walls.
