How much more blood does the heart pump during exercise compared to rest?

During exercise, the heart's demand for blood increases significantly to supply oxygen and nutrients to the working muscles. The correct choice indicates that the heart can pump approximately four to five times more blood during intense physical activity compared to when a person is at rest. This increase in cardiac output is a physiological response to meet the higher metabolic needs of the body during exercise.

Factors such as an increase in heart rate and stroke volume contribute to this substantial rise in blood flow. While the heart works much harder during vigorous activity, this increase is essential to support the greater levels of oxygen consumption and carbon dioxide removal that occur during exercise.

The other choices suggest lesser or greater increases, which do not fully encapsulate the average physiological response during typical exercise scenarios, where the heart effectively adapts to significant demands placed on it. Thus, understanding this range of four to five times more blood flow during exercise helps underscore the heart's crucial role in physical performance and endurance.