When Heart Rate Increases, the Time Spent In

Question

When heart rate increases, the time spent in
A) systole increases.
B) diastole increases.
C) all phases decreases but most of the decrease is during systole.
D) all phases decreases but most of the decrease is during diastole.
E) isovolumetric contraction increases.

Accepted Answer

When heart rate increases, the duration of each cardiac cycle decreases, meaning that both systolic and diastolic phases are shortened. However, the decrease is more significant during diastole than during systole. Therefore, the correct option is D, where it is stated that all phases decrease, but most of the decrease is during diastole.