What is the unit used to measure blood pressure?

Blood pressure is measured in millimeters of mercury, abbreviated as mmHg. This unit originates from historical practices in which mercury columns were utilized in measuring devices called sphygmomanometers. When assessing blood pressure, the height of the mercury column reflects the pressure exerted by blood against the walls of the arteries.

In contrast, the other units listed do not pertain to blood pressure measurement. Foot pounds refer to a unit of work or energy, pounds per square inch (psi) is commonly used in measuring pressure in various mechanical contexts, and newtons per second measures force over time, which is unrelated to blood pressure. Therefore, the correct measurement for blood pressure is indeed in millimeters of mercury.