抄録
Subjects were exposed in a climatic chamber for 60 min to air temperatures at -5°C, -20°C and -30°C wearing cold-protective clothings. The following manual functions were studied as a function of air temperatures, upper limb skin temperatures, mean skin temperatures or mean body temperatures: handgrip strength, pinch strength, bolt-removing task and counting task. The decline of skin temperatures was observed during cold exposure, wearing cold-protective clothing. At 60 min of cold exposure to air temperatures at -5°C, -20°C and -30°C, mean skin temperatures were 30.2°C, 27.8°C and 26.5°C respectively, then II-right-finger skin temperatures were 20.7°C, 13.1°C and 11.8°C respectively. There were reductions only on limited number of manual functions as compared with functions under normal conditions, that is, bolt-removing task and handgrip strength did not significantly change during cold exposure, whereas pinch strength and counting task decreased with lower surface temperatures and body temperatures. Body or surface cooling resulted in reductions in pinch strength by the order of 50%. The rising of the body storage index, which was calculated from the change of the mean body temperature, resulted in a linear decrease in counting task. The capacity to perform manual handling task and muscle strength appeared to vary according to the muscle used for these performance and depending on the levels of cold stress. Body cooling, combined with local upper limb cooling, produced the largest performance decrements.
