Your blood pressure is a measure of the activity of your heart in pumping, and of the resistance created by the size and the hardness of the walls of the blood vessels. When the doctor measures your blood pressure he puts an inflatable cuff around your arm, then stops the blood flow by pumping air into the cuff; then he listens with a stethoscope to get the pressure at the time when the heart was contractedsystolic pressure-and when it has dilated or relaxed-diastolic pressure. The pressure is taken by a column of mercury measured in millimeters or by a spring device calibrated to the mercury column.
Normal or average blood pressure may range from 95 to 160 systolic and 65 to 90 diastolic. There may be a range in the systolic pressure from 85 to 300 and in the diastolic pressure from 40 to 160. The pressure may vary with sleeping or waking, sitting or standing, with exercise, lack of oxygen or anemia; with chilling, anger, anxiety, frustration or the height of pleasure.