The effects of the preceding swimming in cold water on the submaximal and exhaustive cycling

Abstract

Six trained male swimmers participated in the present study as subjects. They swam in water at 20℃ and 27℃ for each 30 minute, and rode on a bicycle ergometer for 30-min submaximal cycling and exhaustive cycling. At the termination of the swimming at 20℃, rectal temperature (T_<re>) was significantly lower when compared to the swimming at 27℃ (20℃: 36.29 ± 0.77℃, 27℃: 37.15 ± 0.39℃). During the submaximal cycling after 30-min swimming at 20℃,heart rate (f_H) was consistently lower (p<0.05) than the swimming at 27℃ until 20 min of cycling. The mean difference of f_H was 12 beats/min. During the exhaustive cycling which followed 3O-min swimming at 20℃, the peak heart rate (peak f_H) and oxygen uptake (peak V_<o2>) were significantly lower compared to 30-min swimming at 27℃: 169 ± 7 beats/min, 3155 ± 117ml/min (46.3 ml/kg・min^<-1>) and 150 ± 8 beats/min, 2928 ± 148 ml/min (42:9 ml/kg・min^<-1>),respectively. The peak fH and exhaustion time were significantly correlated to the rectal temperature at the beginning of the exhaustive cycling. As for the concentration of blood lactate and free fatty acids, no significant differences between 20℃ and 27℃ trials were observed during both submaximal and exhaustive cyclings. From these observations, it is concluded that the decrease in rectal temperature and the increase in oxygen uptake observed during 30-min swimming at 20℃ as compared to the swimming at 27℃ resulted in the decrease of fH until 20min of post-swimming submaximal cycling and in the decrease of peak f_H, peak V^^._<o2> and performance time during post-swimming exhaustive cycling. These findings suggest that swimming in cold water, which is frequently observed on an actual triathlon race, would have some detrimental effects on the performance of post-swimming cycling.