Chrome domes: sweat secretion from the head during thermal strain
The importance of the head in dissipating body heat and the prevention of heat illness under hot conditions is well recognised (Desruelle and Candas, 2000), although little is known about the local differences in sweat secretion within the head. In this study, we focussed on this sweat distribution, since such information will contribute significantly to our understanding of thermoregulation in general and of human sudomotor control in particular. Despite its relatively small surface area (6-7% of total area; Hardy and DuBois, 1938), the head is highly vascular, and has a surface area-to-mass ratio that favours heat loss. Indeed, heat loss per unit area is significantly higher from the head than most other body segments (Froese and Burton 1957; Rasch et al., 1991). In addition, when the body is covered with clothing, the head becomes a major avenue for heat dissipation, but this is adversely influenced by helmets and other headgear. Therefore, it is most important, either for the development of thermal (head) manikins or for the design of headgear, that the sweat secretion patterns of the head are known across a wide range of thermal loads. In this project, the sweating responses of nine non-glabrous (hairy) skin surfaces of the scalp and the forehead were measured in shaved males.