CLOTHING AND EXERCISE .2. INFLUENCE OF CLOTHING DURING EXERCISE WORK IN ENVIRONMENTAL EXTREMES

Thermoregulatory studies often investigate thermal responses without c onsidering the influences of clothing. These studies have expanded our understanding of basic human responses to various environmental condi tions. However, human thermoregulation is variable and modified by hea t transfer interactions between skin surface area, clothing and enviro nment. Much of the original work on the influence of clothing on work performance was the result of ergonomic concerns. Currently, the impor tance of clothing and the influence of new clothing technology aimed a t minimising thermal stress has spawned a new interest. For hot climat es, new fabrics have been developed with improved wicking properties t o keep the wearer cooler and drier, and to enhance heat transfer from the body while providing greater comfort. In contrast, the challenge o f cold environments requires a different approach to clothing, which t ries to minimise the free movement of air and water along the skin sur face of the body. The materials used should also be able to absorb rad iant heat from the environment and be nonconductive. In a cold climate , the wearer needs to balance the need for a clothing barrier for warm th with the potential for accumulating too much heat as the result of metabolic heat production from exercise. To counteract this potential problem, it is suggested that cold-weather clothing be worn in layers that can be removed during exercise and replaced during less active pe riods. Protective clothing for firefighters, hazardous waste workers a nd astronauts, and athletic protective gear, have specialised design r equirements which may be influenced by considerations, for example, of environmental conditions, garment weight, the need for durability, im pact forces.