Comparison of Body Water Turnover in Endurance and Age - matched Sedentary Men

This study compared the body water turnover in endurance athletes and age-matched sedentary men. Eight competitive enduranee athletes (20.8 ± 1.9 yr) and age-matched eight sedentary men (21.6 ± 2.5yr) participated in this study. Total body water and body water turnover were measured using the deuterium (D20) dilution technique. Urine samples were obtained every day for 1Odays after oral administration of D20, The day-by-day concentrations were used to calculate the biological halflife of D?O and body water turnover. Maximal oxygen uptake (V02...) and oxygen uptake corresponding to ventilatory threshold (V02vT) as an index of aerobic capacity were determined uring a graded exercise test. Both V02.,. and V02vT were higher in the exercise group than in the sedentary group (P<O.05). The biological halfLlife of D20 was significantly shorter in the exercise group than in the sedentary group (5.89 ± O.81days vs, 7.52± 0.77days, P<O.05), and the percentage of the body water turnover was significantly higher in the exercise greup than in the sedentary group (11.99 ± 1.96% vs. 9.39± 12L%, P<O.05), The body water turnover was correlated with VO!.,. and VO!vT, respectively (P<O.05). Based on these findings, this study speculates that a Ievel of physical activity may induce a body water turnover higher in the healthy state, since the better trained subjects have a higher body water turnover. J Physiol Anthropol Ampt Htiman Sci 22 (O: 311-315, 2003 http:flwww. jstage.jst.go.jp/enl