The improved heatproof cap was tentatively designed for the purpose of preventing heat storage and dampness. In order to investigate the effect of putting on the improved heatproof cap against the heat radiation, two experiments were carried out in summer.
　The first experiment was a comparison of skin temperature of parietal region between putting on the improved heatproof cap and various kinds of headgears in resting condition on 13 subjects.
　The second experiment was a comparison of the physiological responses between putting on the improved heatproof cap and the baseball cap during exercise. In this experiment, four healthy men were loaded by a bicycle ergometer at 450 kpm/min for 30 minutes under the vertical heat radiation of 1.3 cal/cm²/min in a room of 35℃ with 60% relative humidity and 2.0 m/sec air flow.
　The results are as follows:
　1) The protection against the heat radiation in case of putting on fishing hat, improved heatproof cap, heatproof ventilating hat and helmet hat were better than that of the other headgears.
　2) In average, the values of total sweat volume of back, rate of body weight loss and skin temperature rise of parietal region in case of putting on the improved heatproof cap and the baseball cap during exercise were significantly smaller than those of no headgear respectively.
　3) During exercise, the temperature and humidity of inner air space in the improved heatproof cap were lower than those of the baseball cap. The value of skin temperature rise of parietal region of putting on the improved heatproof cap was smaller than that of the baseball cap.

DESCENTE SPORTS SCIENCE Vol.33/THE DESCENTE AND ISHIMOTO MEMORIAL FOUNDATION FOR THE PROMOTION SPORTS SCIENCE