Analysis of Heat-Exercise Cross Adaptation in Hot Dry Sauna

熱帯地非スポーツマン(タンザニア)と日本人スポーツマン(短距離走者)を環境制御実験装置(気温28℃,湿度60%)に安静にさせた後,低温サウナ(60-70℃)で30分間暑熱負荷を加え(n=4 period),体重,皮膚温,心拍数,血圧,呼吸数,代謝量の変化を連続記録解析した.暑熱負荷中の熱帯地非スポーツマンの心拍数・代謝量の増加率は日本人スポーツマンの増加率より低かった.しかし熱帯地非スポーツマンでは,かなりの呼吸数増加が観察され,特に深呼吸後に見られた浅速呼吸は,ヒトに熱放散現象であるパンディング現象の残存が示唆された.この熱帯地非スポーツマンから得られた結果は遺伝的に獲得された熱耐性であり,日本人スポーツマンのそれは暑熱と運動の協調による体温調節反応量の増加によると考えられる.A tropical resident (non-sportsman) and a Japanese sportsman (sprinter) were the subjects in this study. The changes in metabolic rate, respiratory rate, pulse rate, blood pressure, skin temperature and body weight during 30 minutes sauna heat load (60-70℃) were measured after 30 minutes resting in the climate chamber (28℃, 60% r.h.). The mean increase of pulse rate and metabolic rate in the tropical subject were small compared to those of the Japanese sportsman (in both subjects, n=4 period of experiments). But considerable increase of respiratory rate and in a few case the rapid and shallow breathing similar to thermal panting were observed in the tropical subject. The results obtained from the tropical subject may be closely related to his inherent constitutional characteristic and his acquired heat tolerance, and those of the Japanese sportsman may be due to the enhanced ability of heat production and effective heat loss response owing to larger cross adaptability by co-operation of heat and exercise load