PROJECT-AQUARIUS .10. EFFECTS OF WORK, WEATHER, AND FIRE ON THE ENERGY-EXPENDITURE, STRAIN, AND PRODUCTIVITY OF MEN SUPPRESSING WILDLAND FIRES

Four crews of male firefighters were studied while they attempted to s uppress well-developed experimental bushfires of intensities commonly faced by hand-tool crews, and also while they built fireline in the sa me way without fire, during three summers in Australian eucalypt fores ts. Multiple-regression analyses of their responses showed that they m aintained their deep body temperature and heart rate at constant and s ustainable levels over a wide range of work duration and intensity, an d of heat from weather and fire that frequently exceeded the limits re commended in current heat-stress guidelines. Energy expenditure declin ed slightly with warmer weather and fire although not with rake durati on. Productivity was unchanged by warmer weather but declined slightly with rake duration and with fire. The findings confirm the effectiven ess of the firefighters' work practices that allowed them to set their own pace, and of their light, well ventilated clothing that permitted unrestricted evaporation of sweat.