Hypothermia and Hyperthermia

Publisher Summary This chapter focuses on the central neural control of thermoregulation and regulation of body temperature in thermoneutral environments. The main area which controls body temperature within the central nervous system is the preoptic area of the anterior hypothalamus (PO / AH). This region contains temperature-sensitive and temperature-insensitive neurons which interact to regulate the systemic thermoregulatory response to a given environment or situation. During most daily activities in healthy people, only minor changes in heat dissipation are required to maintain normothermia during changes in activity or when one moves to a slightly warmer or cooler environment. During exposure to cold environments, the goal of the thermoregulatory response is to maintain core body temperature, or to minimize any drops in body temperature that may occur. Human exposure to hyperthermia is usually due to some combination of environmental heat exposure or exercise. Physiological thermoregulatory responses to heat in humans are much more efficient than responses to cold. Therefore, physiological thermoregulation is primary during hyperthermia.