Which exercise mode significantly enhances venous return, positively impacting stroke volume and cardiac output?

The exercise mode that significantly enhances venous return, positively impacting stroke volume and cardiac output, is resistance exercise. This is primarily due to the muscle pump effect, which occurs when skeletal muscles contract and compress the veins during resistance activities. As muscles contract, they help push blood back toward the heart, thereby increasing venous return. This process can lead to an increase in stroke volume, which is the amount of blood the heart pumps out with each beat, and subsequently improve cardiac output.

Additionally, resistance training can stimulate adaptations in the cardiovascular system, enhancing the heart's efficiency and capacity. While aerobic exercise also plays a crucial role in improving cardiovascular health and venous return, resistance exercise has a particularly pronounced effect due to the concurrent activation of multiple muscle groups and the mechanical compression of veins during lifting movements.