Abstract
The efficiency of man-machine system is influenced by the atmospheric conditions within which the human activities are carried out. One of the important aspect of the environments is that of temperature. Impairment of finger dexterity in various thermal conditions was observed by FD test and tapping rate. A marked drop of finger dexterity was showed at about below 23°C of dorsal hand skin temperature in spite of various outer environmental conditions. This level of the skin temperature was interpreted as additional evidence to the observations that seasonal variations of regional skin temperature, vascular reflex, and insensible perspiration of dorsal hand showed remarkable quantitative and also qualitative changes at about 23°C of skin temperature.
The decrement of manual dexterity is probably caused by some arm circulatory conditions.
