In what unit is blood pressure recorded?

Blood pressure is recorded in millimeters of mercury (mmHg) because this measurement reflects the height of a column of mercury that is displaced by the pressure exerted by the blood within the arteries. The use of mercury in measuring blood pressure dates back to the invention of the sphygmomanometer, a device used to measure blood pressure, which uses a column of mercury to visually indicate pressure levels.

Although other units like centimeters of mercury or pascals exist, they are not typically used for blood pressure readings. Centimeters of mercury could technically be used since 1 cmHg equals 10 mmHg, but standard practice prefers mmHg for consistency and familiarity within the medical community. Pascals, being a unit of pressure in the International System of Units (SI), is not commonly utilized in clinical settings for blood pressure, even though they are scientifically valid. Therefore, millimeters of mercury is the widely accepted and understood unit for recording blood pressure.