What vasodilatory response is associated with thermotherapy?

• A. Vasoconstriction
• B. No change
• C. Vasodilation
• D. Spasm

Answer: (C)

Heat from thermotherapy raises tissue temperature, causing small arteries and arterioles to relax and widen. This vasodilation increases blood flow to the treated area, helping to deliver oxygen and nutrients and remove waste products. The mechanism involves smooth muscle relaxation and local mediator release (such as nitric oxide), sometimes with a reflex neurogenic contribution, all promoting dilation. So the expected vascular response to thermotherapy is vasodilation. Vasoconstriction would reduce flow, no change implies no effect, and spasm would mean sudden contraction, none of which describe heating.