The goal of thermotherapy through the application of heat or cold (cryotherapie) modalities is to change the cutaneous, intra-articular, and the core temperature of the muscle with the aim of improving pain symptoms of some certain conditions. This method induces change in tissue temperature in a targeted region that has the goal of inducing a certain and favorable biological response.
Heat treatment is designed to increase the temperature of the muscle that will help in increasing the bloodflow that will result to vasodilation. Heat accelerates tissue healing because of increased bloodlfow in the muscles.
Cold treatment will decrease the bloodflow in the muscles causing vasoconstriction. Decreased metabolic rate due to cold treatment limits the extensio of tissue injuring and it helps the tissue to survive cellular hypoxia due to increased bloodflow, inflamation, conduction rate, and excitability.