Abstract
The present study was carried out to investigate the effect of energy intake levels on the interrelationship between dermal nitrogen loss and urinarp nitrogen excretion during exercise. Urinary, fecal and dermal nitrogen losses were analysed daily with four male subjects during three consecutive periods of 6-7 days; control-maintenance energy (CM), exercise-maintenance energy (EM) and exercisehigh energy (EH) periods. Nitrogen intake level was 190mg/kg/day in all periods and energy supplies were 44 kcal/kg/day in CM and EM periods and 52kcal/kg/day in EH period. During exercise periods, treadmill running of ten minutes was loaded three times with intervals of ten minutes, from 10: 00hr to 11: 00hr in the morning.
The amounts of urinary nitrogen excretion both rn the mean values and in each subject were in the order of EM>CM>EH periods, and were significantly low in EH period compared with those in EM and CM periods. Exercise loading induced transient increase of urinary nitrogen excretion for one hour immediately after exercise in both EM and EH periodS. In EH period, urinary nitrogen excretion for 24 hours was decreased compared with that in CM period, because of subsequent decrease. The amounts of dermal nitrogen loss were in the order of EM>EH>CM periods with significant differences. Nitrogen balances in CM and EM periods were almost the same, but in EH period significantly greater positive nitrogen balance was observed compared with those in CM and EM periods.
