What can increase cardiac output?

Cardiac output is the volume of blood the heart pumps per minute, and it can be influenced by several factors. An increase in blood volume is one of the key factors that can enhance cardiac output. When blood volume increases, the heart receives more blood returning to it from the veins during diastole (the heart's relaxation phase), which can lead to a greater stroke volume (the amount of blood pumped with each heartbeat). According to the Frank-Starling law of the heart, within physiological limits, an increase in the amount of blood in the heart before contraction (preload) stretches the heart muscle, which can enhance its contractions and result in increased cardiac output.

In contrast, decreased blood pressure may negatively impact the force that drives blood flow and could lead to a reduced cardiac output. Similarly, a reduction of heart rate often means that the heart is beating less frequently, which typically yields a lower cardiac output unless it is compensated by a significantly increased stroke volume. Stabilizing cholesterol levels, while important for overall cardiovascular health, does not directly affect the mechanics of cardiac output. Therefore, increasing blood volume stands out as the factor that can effectively lead to an increase in cardiac output.