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Cardiac Output — FRCA Primary MCQ

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EasyPhysiology - CardiovascularCardiac OutputFRCA Primary

What is the approximate average resting cardiac output of a healthy 70 kg adult?

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Correct answer: C5 L/min

Explanation lettering: B = shown as A · A = shown as B · D = shown as C · E = shown as D · C = shown as E

The correct answer is D, 5 L/min. Cardiac output is the volume ejected by one ventricle each minute and equals heart rate × stroke volume. Using standard resting values for a healthy 70 kg adult, 70 beats/min × 70 mL/beat = 4900 mL/min, or 4.9 L/min, which rounds to 5 L/min. Contemporary measurements in healthy adults report a mean resting cardiac output of about 5.2 L/min. Options A (2 L/min) and C (3 L/min) are too low for the average healthy resting adult. Option E (8 L/min) may occur near the upper end of normal variation but is not the approximate average requested. Option B (10 L/min) is more consistent with exercise or a high-output state than normal rest.

Reference: Schweitzer R et al. Establishing Cardiac MRI Reference Ranges Stratified by Sex and Age for Cardiovascular Function during Exercise. Radiology: Cardiothoracic Imaging. 2025;7(3):e240175. https://pubmed.ncbi.nlm.nih.gov/40471075/