This study was conducted to examine effect of forearm cooling on body temperature responses during exercise in a warm environment. Vo₂, heart rate, rectal temperature, skin temperature, body weight and local sweat volume during cycling with submaximal intensity (60% Vo₂max) of five trained and five untrained students were measured. All subjects exercised on bicycle ergometer for 50 minutes and their left forearm were exposed to cold air (-10°C) in the last 20 minutes during the exercise. The results were as follows :
1. Vo₂ and heart rate decreased 10% in the trained group, 9% in the untrained group when they were examined 2 ~ 3 minutes after the cooling condition started.
2. Rectal temperature and mean skin temperature rose during the exercise and fell immediately after the cooling. The mean truncus skin temperature also slightly fell after the cooling, but the fall was smaller than those of rectal temperature and mean skin temperature. The skin temperatures of the trained group were consistently higher than those of the untrained group.
3. The decrease in body weight of the untrained group after the exercise were significantly larger than that of the in trained group. The local sweat volume of chest were significantly increasing since the beginning of the exercise, but they were restrained in the cooling condition.
　It was suggested that exposing a part of body to cold air during exercise in warm environment decrease stress in the respiratory system and the circulatory system, and restrain rise in body temperature and increase in sweat volume.

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