Since the thermal conductivity of water is about 23 times that of air, as a result of exposing the body to cold water environment, there is a decrease in peripheral muscle temperature due to heat radiation from the skin. Decrease in aerobic metabolism (Wakabayashi et al., 2017) and elevation of blood lactate concentration (Ogaki, 1995) have been reported as an influence of exercise in a state in which the lower muscle temperature. However, the results clarified in these studies are transient, and no change in physiological response by training has been observed.
The purpose of this study was to clarify an effect of exercise training by lactate threshold level intensity under lower muscle temperature condition due to cold water. In this study, adult male participants were divided into two groups (cold water condition group and control condition group). The cold water condition group was immersed in water at 15°C for 30 minutes to reduce the muscle temperature and then exercised while maintaining the inundation at the same water temperature. In the control condition group, the same contents as in the cold water condition group were performed at a water temperature of 33°C. The exercise was a 30 minute Lactate threshold level intensity bicycle exercise, which was carried out three times a week for 4 weeks. Also, in order to observe changes in performance due to train during lower muscle temperature conditions, we measured the Wingate test, lactate threshold level intensity and VO2max before and after the experiment.
As a result of this study, 1) Lower muscle temperature due to immersion in cold water condition group was observed, 2) Exercise in a state where the muscle temperature was low reduced aerobic metabolism mobilized to exercise, 3) Exercise at the lactate threshold level intensity in the state of lower muscle temperature further mobilized glycolytic metabolism, 4) Improvement of peak power and average power of the Wingate test in the cold water condition group were observed.