Final answer:
The term for the increase in heart rate during steady-state aerobic exercise is Cardiac Drift. It is distinct from tachycardia, bradycardia, and arrhythmia, which are different conditions related to heart rate and rhythm.
Step-by-step explanation:
The term given to the gradual increase in heart rate during a steady-state bout of aerobic exercise is C) Cardiac Drift. This is not to be confused with tachycardia, which is a heart rate that is too fast (above 100 beats per minute in adults), or bradycardia, which is a heart rate that is too slow (below 60 beats per minute). While arrhythmia refers to an irregular heartbeat, cardiac drift specifically describes the scenario where the heart rate increases gradually during extended periods of exercise despite maintaining a constant exercise intensity.