How does cold therapy primarily affect blood vessels?

Cold therapy primarily induces vasoconstriction of arterioles and venules. When cold is applied to an area, it causes the blood vessels to constrict, which reduces blood flow to that region. This physiological response is beneficial in controlling inflammation and swelling following an injury. By minimizing blood flow, cold therapy helps to lessen the accumulation of excessive fluid in the tissues, thereby addressing edema and pain.

In contrast, it is important to recognize that while the immediate effect of cold therapy is vasoconstriction, there can also be subsequent reactions, such as a rebound effect where the vessels may dilate once the cold application is removed. However, the primary impact during the application is vasoconstriction.