[Campbell Biology P.978] Suppose that after you exercise regularly for several months, your ... | Practice Question

Suppose that after you exercise regularly for several months, your resting heart rate decreases, but your cardiac output at rest is unchanged. Based on these observations, what other change in the function of your heart at rest likely occurred?

  • A: Increased stroke volume.
  • B: Decreased blood pressure in the arteries due to reduced cardiac output.
  • C: Reduced efficiency of oxygen exchange in capillaries.
  • D: Faster electrical impulse conduction through the AV node.

Explanation

Cardiac output CO is the product of heart rate HR and stroke volume SV CO = HR x SV . If resting heart rate decreases, but cardiac output remains unchanged, then stroke volume must have increased to compensate. This is a common physiological adaptation to regular exercise, where the heart becomes more efficient, pumping more blood with each beat.