Effects of repeated exercise/rest sessions at -10 degrees C on skin and rectal temperatures in men wearing chemical protective clothing.

The development of thermophysiological responses during four consecutive exercise/rest sessions in the cold was studied in men wearing chemical protective clothing and a face mask. Six men repeated four exercise/rest sessions during 8 h at -10 degrees C. Each session consisted of step exercise (240 W x m(-2)) for 60 min and rest for another 60 min. Rectal and skin temperatures were measured continuously and thermal sensations were obtained at 30-min intervals. Entering the cold from a warm environment and the onset of exercise resulted in a decrease in skin temperatures during the first session and the decrement in the temperatures of the extremities continued for 10-20 min during the following period of exercise. Torso skin temperature was at its lowest during the first rest period. After the first session of cold exposure the range and the level of variation in mean body temperature (Tb) followed a pattern which was repeated until the end of the experiment. However, the torso skin temperatures increased gradually until the fourth session, while the temperatures of the extremities, in contrast, tended to decrease up to the third session. In conclusion, the present results indicated that although Tb, reflecting the whole body heat balance, showed a typical pattern of change after the first session (2 h), the torso area was warming until the end of the cold exposure while the extremities continued to cool down up to the third session (6 h), obviously due to a prolonged redistribution of the circulation.