<unk>  refers to the difference between the rates at which the heart pumps blood - at any given time versus its maximum capacity. A measurement of the<unk>  may be a health indicator for some medical conditions.<unk>  may be 4-5 times greater than a resting value for a healthy person. __TOC__
Cardiac reserve
Vagal tone
Cardiac cycle
Heart rate variability
Myogenic tone
Myocardial contractility
Cardiac output
Coronary reflex