Footnote

a Blood pressure is measured by the distance, in millimeters, it elevates a column of mercury. The upper and lower pressures caused by the beating and relaxing of the heart are called the systolic and diastolic pressures. These vary in individuals as a result of their age, sex, mental and physical stress, and fatigue. Blood pressure tends to be lower in women than in men, lower in children, and higher in the elderly. Although opinions may vary slightly, a healthy young person may have a reading of 100 to 140 millimeters of mercury systolic, and 60 to 90 millimeters diastolic.