What factors mediate the increase in blood flow to skeletal muscles during exercise?

The increase in blood flow to skeletal muscles during exercise is primarily mediated by increased cardiac output and vasodilation. When the body engages in physical activity, the heart rate rises and stroke volume increases, leading to a greater overall cardiac output. This elevated output pumps more blood through the circulatory system, allowing for enhanced delivery of oxygen and nutrients to the working muscles.

Additionally, vasodilation occurs in the peripheral blood vessels supplying the skeletal muscles. During exercise, metabolic byproducts such as carbon dioxide, lactic acid, and adenosine accumulate in the muscle tissue, leading to the relaxation of smooth muscle cells in the vascular walls. This response facilitates the dilation of blood vessels, thereby increasing blood flow to areas with a high demand for oxygen and nutrients. Collectively, these mechanisms ensure that the active muscles receive the necessary support to perform effectively during exercise.

The other choices present factors that do not assist in mediating increased blood flow during physical activity. For example, increased peripheral resistance would actually reduce blood flow, while a decrease in stroke volume would hinder cardiac output, impacting how effectively blood is delivered to muscles. Similarly, reduced oxygen demand does not align with the physiological needs during exercise, where there is a direct increase in oxygen demand as muscular activity increases.