What factor most limits a person's maximal increase in cardiac output during exercise?
A)the time available to fill the heart chambers with blood as the heart rate increases
B)the time it takes for electrical impulses to reach all parts of the heart
C)the rate at which cardiac muscle contracts
D)the rate at which oxygen is delivered to the cardiac muscle cells
E)the total amount of blood in an individual

Question

Quizplus · Accepted Answer

During exercise, the heart rate increases, which means the time available to fill the heart chambers with blood decreases. Therefore, the factor that most limits a person's maximal increase in cardiac output during exercise is the time available to fill the heart chambers with blood as the heart rate increases, as indicated in choice A.

What Factor Most Limits a Person's Maximal Increase in Cardiac