This chapter outlines the physical and physiological changes that occur during growth
and maturation and the possible effects these changes can have on the nature and
effectiveness of thermoregulation. The physiological responses to heat stress are
discussed in terms of metabolic, circulatory, hormonal, and sweating responses,
changes in body temperature, and in terms of heat tolerance. Also discussed is
hydration status, which can affect thermoregulatory effectiveness in the heat. The
physiological response to cold stress is considered in terms of the metabolic and
circulatory responses and their possible influence on the effectiveness of
thermoregulation. The discussion does not outline the thermoregulatory response per
se, but rather emphasizes the differences in that response between children and
adults. Finally, child–adult differences in the acclimatization- and training-induced
adaptations to thermal stress are discussed.