The purpose of this study was to investigate the effect of head heating on physiological responses, especially the cardiac output and tympanic membrane temperature at rest and during submaximal exercise (25%Vo₂max and 50% Vo₂max). The cap to supply the heat load to the head was prepared. The tube sewn onto the inner surface of the cap was connected to the thermostated bath. The supplied inlet water temperatures were 20, 25, 30, 35, 40, 45 and 50°C with a flow of 1.2 l/min. The skin temperature of the dorsal side of the hand showed the positive correlation with the tympanic membrane temperature at rest and the work intensity of 25% Vo₂max.
　The cardiac output showed the positive correlation with the tympanic membrane temperature. It was supposed that the measure of tympanic membrane temperature might be useful to evaluate the efficiency of heat protection from the heat stress like a solar heat radiation by wearing the hat and cap.

DESCENTE SPORTS SCIENCE Vol.13/THE DESCENTE AND ISHIMOTO MEMORIAL FOUNDATION FOR THE PROMOTION SPORTS SCIENCE