Cold-induced thermogenesis is the fundamental characteristic of endothermic thermoregulation—the capacity to produce heat by speeding up metabolism in reaction to cold. Cold fibers cause transitory afferent discharges when a tiny surface area is exposed to cold, such as during Cold Abdomen Pack application. This results in a drop in skin temperature as well as cold sensation and heat-gain responses. Hypothalamic impulses to constrict peripheral blood arteries are linked to exposure to cold.

    Consequently, the deeper vascular system experiences compensatory vasodilatation, increasing blood flow to the tissues underneath the site of exposure and raising the metabolic rate to sustain stable deep tissue temperature. For instance, immersion in cold water at 20°C nearly doubles metabolic rate, whereas at 14°C it more than quadruples, according to a prior study.