How is blood pressure mathematically expressed in relation to cardiac output and total peripheral resistance?

Blood pressure is fundamentally expressed in terms of the relationship between cardiac output and total peripheral resistance through the equation:

Blood Pressure = Cardiac Output × Total Peripheral Resistance.

This equation illustrates how blood pressure is influenced by how much blood the heart pumps (cardiac output) and the resistance to blood flow in the systemic circulation (total peripheral resistance).

Cardiac output, defined as the volume of blood the heart pumps per minute, contributes to the pressure generated within the arterial system. If the body requires more blood flow to tissues (increased demand), cardiac output may increase, which can raise blood pressure if resistance remains constant. Conversely, if total peripheral resistance decreases (as seen in vasodilation), this typically would reduce blood pressure if cardiac output were to remain unchanged.

Consequently, the multiplying relationship captures the interdependence of these two factors—either an increase in cardiac output or an increase in total peripheral resistance can lead to an increase in blood pressure.