Normal cardiac output is within which range?

• A. 2-4 L/min
• B. 8-12 L/min
• C. 4-8 L/min
• D. 6-10 L/min

Answer: (C)

Cardiac output is the amount of blood the heart pumps each minute, and it comes from multiplying heart rate by stroke volume. At rest, a typical heart rate is about 60–100 beats per minute and stroke volume is roughly 60–100 mL per beat. Multiply those together and you get around 4–8 liters per minute. That range represents normal resting output that keeps tissues perfused while also allowing the heart to ramp up if activity increases. Exercise raises both heart rate and stroke volume, so CO can climb above 8 L/min when demand is high. Values much below 4 L/min suggest insufficient perfusion at rest, while higher values at rest are uncommon and may indicate other conditions.