The difference between maximum cardiac output during peak exercise and resting cardiac output is known as what?

1. Because the heart is a muscle, regular exercise increases its pumping efficiency. 2. During exercise, both heart rate and stroke volume can rise, increasing cardiac output several-fold above resting levels. 3. The difference between this maximum cardiac output and the resting cardiac output is known as the cardiac reserve, which measures the heart's residual pumping capacity. 4. Ejection fraction, stroke volume, and afterload are all separate measured or calculated quantities, not the difference between maximum and resting cardiac output. _Source: OpenStax Anatomy and Physiology (CC BY 4.0), Ch 19 "The Cardiovascular System: The Heart", section 19.4, p. 866_