Blood pressure refers to the amount of pressure applied to the interior of blood vessels due to circulating blood. A high blood pressure means the heart is working harder than it should to pump blood. A numerical system measures the extremes of pressure in the body.
Systolic Pressure
The systolic pressure in the body is the larger number in the reading of blood pressure, according to the National Heart, Lung and Blood Institute. Systolic pressure is the pressure recorded while the heart is actively pumping.
Diastolic Pressure
The diastolic blood pressure is recorded between beats of the heart, while the heart muscle is at rest. Since the heart isn't pumping, this number is always lower than the systolic pressure.
Blood Pressure Readings
The American Heart Association recommends a systolic at or below a pressure of 120mm of mercury, and a diastolic at or below a pressure of 80mm of mercury. Readings higher than this can result in prehypertension, a condition in which systolic/diastolic readings are between 120/80 and 139/89mm of mercury. Hypertension may be diagnosed when systolic/diastolic readings are chronically at or above 140/90mm of mercury.
