Rate-pressure product (RPP) is calculated as which of the following?

• A. HR × diastolic BP
• B. HR × systolic BP
• C. HR × mean arterial pressure
• D. HR × pulse pressure

Answer: (B)

Rate-pressure product measures myocardial oxygen consumption and cardiac workload during activity. It is found by multiplying heart rate by systolic blood pressure. The key reason this uses systolic BP is that the heart must generate the peak pressure during systole to eject blood, and this peak load largely determines the amount of oxygen the heart muscle needs. Diastolic blood pressure reflects pressure during filling, not the peak effort of contraction. Mean arterial pressure is an average of pressures over the cycle and doesn’t capture the peak systolic load as directly. Pulse pressure (the difference between systolic and diastolic) relates to arterial stiffness and stroke volume but isn’t the direct driver of the heart’s workload. So, multiplying heart rate by systolic BP gives the best estimate of the heart’s oxygen demand during exercise.