The effect of hand immersion on body temperature when wearing impermeable clothing.

The effects of hand immersion on body temperature have been investigated in men wearing impermeable NBC clothing. Six men worked continuously at a rate of approximately 490 J. sec-1 in an environmental temperature of 30 degrees C. Each subject was permitted to rest for a period of 20 minutes when their aural temperature reached 37.5 degrees C, and again on reaching 38 degrees C, and for a third time on reaching 38.5 degrees C (three rest periods in total). Each subject completed three experimental conditions whereby, during the rest periods they either: a. Did not immerse their hands (control). b. Immersed both hands in a water bath set at 25 degrees C. c. Immersed both hands in water at 10 degrees C. Physiological measures of core temperature, skin temperature and heart rate were recorded at intervals throughout the experiment. Measures of mean aural temperature and mean skin temperature were significantly (P less than 0.05) reduced if hands were immersed during these rest periods, compared to non immersion. As a result, the total work time of subjects was extended when in the immersed conditions by some 10-20 minutes within the confines of the protocol. It is concluded that this technique of simple hand immersion may be effective in reducing heat stress where normal routes to heat loss are compromised.