Chapter 10 - The temperature regulatory system

Abstract

This chapter highlights the contributors to the current understanding of physiological regulation and processes of heat exchange. The temperature regulation occurs through physiological and behavioral processes. Behavioral temperature regulation plays its greatest role in coping with cold environments, whereas both physiological and behavioral temperature regulation operate in hot environments, with physiological regulation perhaps playing the dominant role. Exercise induces both physiological and behavioral regulation by altering heat production, blood flow redistribution for convective heat transfer, and sweating. One of the very earliest investigators of body temperature regulation was Charles Blagden (1748-1820) who performed a variety of investigations in heated rooms using thermometry. Blagden described both internal and body surface temperature differences with different types of heat exposure, along with the documentation of the essential function of evaporative cooling, the differential effects of dry and moist heat, as well as the modification of heat exchange that clothing provides. Although early work in thermometry was focused on disease, there were limited reports dealing with exercise. John Davy (1791-1860) was the first one who gave special attention to the temperatures of healthy persons, including the temperature elevation associated with passive exercise. Davy reported that physical activity of any type elevated heart rate and body temperature, and that these elevations were augmented in warm environments.