What term describes the amount of labor the heart must exert to pump blood?

The term that accurately describes the amount of labor the heart must exert to pump blood is blood pressure. Blood pressure is a measure of the force that the circulating blood exerts against the walls of blood vessels, and it reflects the workload on the heart as it pumps blood throughout the body. When blood pressure is high, it indicates that the heart is working harder to overcome resistance in the arteries, thus requiring more exertion from the heart muscle.

Cardiac output, on the other hand, refers to the volume of blood the heart pumps per minute and is a product of heart rate and stroke volume. While cardiac output is important, it does not directly measure the workload or exertion level of the heart. Heart rate simply reflects how many times the heart beats in a given time frame, and stroke volume is the amount of blood pumped from the heart with each beat. Although these terms are related to cardiac function, they do not specifically represent the labor or effort of the heart in the same way blood pressure does.