Thermophysiology

Thermophysiology is the branch of physiology that studies how organisms generate, regulate, and measure body temperature in response to internal and environmental conditions. It covers the mechanisms by which animals maintain thermal stability, as well as how temperature affects metabolism, organ function, and behavior. A central distinction is between endotherms, which generate metabolic heat to sustain a relatively constant internal temperature, and ectotherms, whose body temperature largely tracks the ambient environment. Within endotherms, homeothermy refers to a stable core temperature, while some species exhibit more variable thermal states.

Core control is centered in the hypothalamus, which integrates thermal signals and coordinates responses such as shivering, non-shivering thermogenesis, vasoconstriction or vasodilation, and behavioral changes like seeking shade or sun. Heat production arises from metabolic heat and specialized pathways such as shivering and non-shivering thermogenesis, the latter involving brown adipose tissue in some mammals. Heat loss occurs through radiation, conduction, convection, and evaporation, with physiological and behavioral adjustments modulating skin blood flow and sweating or panting.

Thermophysiology also addresses acclimation and acclimatization to seasonal or environmental changes, as well as fever and other disease-related thermoregulatory shifts. Measurement and study methods include body-temperature monitoring, thermography, and calorimetry. The field informs medicine, fitness and occupational health, ecology, and evolutionary biology, highlighting how organisms balance heat production and loss to sustain function across diverse climates.