What happens to blood vessels when heat is applied to the skin?

When heat is applied to the skin, blood vessels expand in a process known as vasodilation. This expansion allows for increased blood flow to the area, which is often a response to maintain optimal body temperature or to facilitate the healing process through enhanced circulation. As the blood vessels expand, more warm blood reaches the surface of the skin, which can help to dissipate excess heat, thus aiding in thermoregulation. This physiological response is significant, especially during instances of increased physical activity, warmth, or when treating muscle soreness, as it helps reduce tension and promote relaxation in the affected areas.