CLOTHING AND EXERCISE .1. BIOPHYSICS OF HEAT-TRANSFER BETWEEN THE INDIVIDUAL, CLOTHING AND ENVIRONMENT

Despite large environmental variations, the human body maintains a tig htly regulated core temperature. Effective thermoregulation must balan ce the interaction between skin surface, clothing and ambient air. Ind ices of thermal stress (wet bulb globe temperature, heat stress index, maximum evaporation rate, required evaporative rate and wind chill) p rovide valuable information concerning the heat exchange between the i ndividual and the environment, and serve as protective guidelines whil e working in environmental extremes. The role of clothing, as an inter active barrier. greatly affects thermal balance. Clothing is varied ac cording to prevailing environmental conditions. metabolic heat product ion, gender and age differences, fabric thermal properties design and intended use. Models (static, dynamic and human) have investigated the biophysical transfer of heat between the skin surface area, clothing and ambient air. Additionally, the role of metabolic heat production d uring exercise can greatly influence tolerance to thermal stress durin g a variety of environmental conditions.