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‡ C (II) or 20‡ 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 ~ 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.