What does cardiac output measure?

Cardiac output quantifies the amount of blood the heart pumps into the circulation each minute, reflecting the heart's efficiency in delivering oxygen and nutrients to the body's tissues. It is a crucial measure in understanding cardiovascular health, as it indicates how well the heart is functioning to meet the metabolic demands of the body. By calculating cardiac output as the product of stroke volume (the amount of blood ejected with each heartbeat) and heart rate (the number of beats per minute), healthcare professionals can assess the heart's performance, identify potential health issues, and tailor exercise or treatment programs accordingly.

In contrast, the other options do not directly describe what cardiac output measures. The total volume of blood in the body relates to total blood volume, not the rate of circulation. The efficiency of the heart's valves pertains to how well blood is managed within the heart, rather than the overall quantity of blood being pumped. Lastly, blood pressure in the arteries is a measure of the force exerted by circulating blood on the vessel walls, which is related but distinct from the volume of blood movement represented by cardiac output.