Why does the cardiac output of an endurance athlete often remain relatively stable at rest despite having a significantly lower resting heart rate compared to a sedentary individual?

💡 Explanation

Cardiac output is the product of heart rate and stroke volume. In endurance athletes, stroke volume increases significantly due to adaptations like increased ventricular volume and enhanced myocardial contractility; because of this, cardiac output can be maintained despite a lower heart rate. Therefore, increased contractility and filling explain this phenomenon, rather than sympathetic activity or reduced stroke volume.

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