Comparison between different auxiliary cooling devices in a severe hot/dry climate

Seven different cooling devices were compared under the same hot/dry climatic conditions (50°C, 30% r. h.). Using a Latin-square design, eight male subjects tested water or air-cooled garments (vests or hoods), ice-bag vests, zone cooling or a fan for their beneficial effects on physiological variables. A strain index (SI), computed from sweat rate, change in rectal temperature and heart rate was used to evaluate the physiological status of the subjects while using the different devices. According to the SI, the ice-bag vest had the highest cooling capacity (SI = 0·55), while cooling the torso either by a water- or air-cooled vest or using zone cooling were found to have the same effect (SI ∼ 1). Cooling the head was found to be less effective (SI > 2) while the fan had a minimal cooling effect when compared to control (SI = 3·11 and 3·40 respectively). The results are discussed with respect to the interaction between the cooling capacity of the devices, evaporative heat loss and environmental conditions.