Effects of Heat Stress and Time on Task on Reaction Time1

Several studies have shown that heat stress caused a deterioration in cognitive performance, and that the magnitude of this deterioration was related to the duration of the exposure to high temperature. Particularly in sustained attention tasks, to which some sports activities could be compared, performance decrements were observed under heat stress, and these decrements became more important with the prolongation of the exposure (Mackworth, 1950; Mortagy & Ramsey, 1973). Nevertheless these observations have often been realised without control group, so it was impossible to distinguish between the effect of heat stress, and the effect of time on task.