Cardio-respiratory physical training in water and on land.

Fifteen unconditioned young men, who were similar in maximal aerobic power (VO2 max), were divided into three groups (n = 5 each) and physically trained for one month on a cycle ergometer either on land (I) or immersed to the neck in water of either 32 degrees C (II) or 20 degrees C (III) to determine if physical training (PT) in water and air differ. PT consisted of one-hour daily exercise, 5 times/wk, with exercise intensity readjusted each week to maintain a constant training stimulus of approximately 75% VO2 max (determined on land). Throughout the training period, heart rates (fc) of III averaged 20 and 10 beats . min-1 less than I and II, respectively, despite working at the same VO2 and % VO2 max. Training elicited a 16% increase in VO2 max in I compared to increases of 13 and 15% for II and III, respectively. It was concluded that PT in water produces similar physiological adaptations as does training on land. In cold water, VO2 max is improved despite training with fc significantly lower than that on land.