The initial change in heart rate at the onset of exercise is due to
A) sympathetic stimulation.
B) the withdrawal of parasympathetic inhibition.
C) stretching of the cardiac muscle fibers in response to increased venous return.
D) overfilling of the ventricles.

Question

Quizplus · Accepted Answer

At the onset of exercise, the initial increase in heart rate is primarily due to the withdrawal of parasympathetic (vagal) inhibition, allowing the heart rate to rise.

The Initial Change in Heart Rate at the Onset of Exercise