cardiac reserve
The difference between resting and maximal cardiac output, representing the heart's capacity to increase performance during stress or exercise.
Full Definition
Cardiac reserve quantifies the heart's ability to augment its output above resting levels during periods of increased demand such as exercise or physiological stress. Calculated as the difference between maximal and resting cardiac output, it reflects the combined reserve capacity of heart rate, stroke volume, and myocardial contractility. In healthy young adults, cardiac output can increase 4-6 fold from rest to maximum exercise, representing substantial cardiac reserve. Athletes typically demonstrate enhanced cardiac reserve due to training adaptations including increased stroke volume and improved myocardial efficiency. Reduced cardiac reserve may indicate underlying cardiac pathology and is associated with exercise intolerance and poor functional capacity in sports cardiology evaluations.
Usage
Usage note: Specify units (L/min) when quantifying; distinguish from other cardiac reserve measures.
In Context
- "The athlete's exceptional cardiac reserve of 35 L/min explained her ability to maintain high-intensity performance throughout the competition." — Exercise physiology assessment
- "Diminished cardiac reserve in this young athlete warranted further investigation for possible cardiomyopathy despite normal resting function." — Clinical evaluation report