Which mechanism contributes to vasodilation of skeletal muscle arterioles during exercise?

The mechanism that contributes to vasodilation of skeletal muscle arterioles during exercise is the release of vasodilators. During physical activity, the metabolic demands of the muscles increase significantly, resulting in the production and release of various substances that lead to vasodilation. These vasodilators include adenosine, nitric oxide, and prostaglandins, which help to widen the blood vessels, thus allowing more blood flow to the active muscles.

This increased blood flow is essential because it delivers the oxygen and nutrients needed for increased energy production and removes metabolic waste products that accumulate during exercise. The ability of arterioles to dilate in response to localized factors is crucial for meeting the metabolic needs of skeletal muscle and optimizing performance during exercise.

Other mechanisms such as increased blood viscosity, enhanced sympathetic activity, or increased blood clotting do not primarily contribute to vasodilation in this context. Increased blood viscosity, for example, generally impairs blood flow rather than promoting it, while sympathetic activity typically leads to vasoconstriction in most vascular beds, redirecting blood flow instead of facilitating it. Blood clotting is also unrelated to vasodilation during exercise.