Subjective estimates of physiological responses and perceptual-motor performance in the heat

A total of 31 male and 15 female subjects were selected for the present investigation. The subjects were all in excellent health and ranged in age between 18 and 40 years for the male group and 18 to 24 years for the female group. Four levels of temperature were used: 74 degrees , 90 degrees , 100 degrees and 110 degrees F Wet Bulb Globe Temperature (23.3 degrees , 32.2 degrees , 37.8 degrees and 43.3 degrees C WBGT respectively). The subjects performed four different perceptual-motor tasks. Results indicate that the subjective estimates of physiological responses to heat can be used as a good indicator of the actual changes occurring in physiological responses due to heat exposure. The subjects were more sensitive to changes occurring in body temperature than to changes occurring in the cardio vascular system. Under the extreme hot condition (110 degrees F (43.3 degrees C) WBGT) subjects underestimated the effect on their physiological responses. Perceptual-motor performance is poorly estimated by subjects during heat exposure.