抄録
Five young male subjects with different individual VO2max and similar fat % were examined their thermal and cardiovascular responses to work in water (27 and 31°C and air. During head out immersion, three subma:ximal work (VO2 = 1, 1.5 and 2 1/min) for 30 min on a cycle ergo-meter were perforrned to examine the adaptability to cold in water compared to air. The sub-maximal VO2 during light work in 27°C water was higher than that in 31°C water and air due to shivering. The bradycardia in colder water (27°C) shown during work was compensated by increased stroke volume since the Q during work was the same in air and water. The skin tempera-ture (Ts) in water was almost same as temperature of water and much lower than Ts in air. Despite the linear relationship between the rectal temperature (Tr) and VO2 in air and water, Iower Tr in 27°C water was observed in a given VO2 due to larger heat loss. Although the Tr-% VO2max was linear both in air and water, the slope of the line in colder water was reduced. The present study suggests some interactions between aerobic and cardiovascular capacity on thermai balance in water although the precise relationship is still unknown.
