What is the unit of measurement used to express blood pressure?

Blood pressure is expressed in millimeters of mercury (mmHg), which is a unit that originates from the measurement of the height of a column of mercury that can be supported by the pressure of the blood. This unit of measurement reflects the force exerted by the blood against the walls of the blood vessels during the cardiac cycle, specifically during contraction (systolic pressure) and relaxation (diastolic pressure).

Using mmHg provides a clear and standardized way to represent blood pressure levels, making it easily interpretable for healthcare professionals. The common readings, such as 120/80 mmHg, signify systolic over diastolic pressure, which is crucial for assessing cardiovascular health.

Other units listed, such as liters or pascals, do not relate to blood pressure measurements. Liters measures volume, while pascals measure pressure but are not the conventional unit used in clinical practice for blood pressure. Millimeters per second indicates a rate of movement, which is unrelated to the measurements associated with blood pressure.