Protein Metabolism During Intensive Physical Training in the Young Adult.

摘要

Two groups of men consumed two levels of protein (1.4 and 2.8 g/kg body weight) during a 40-day experimental period. Physical activity and the sweat rates were fairly high during the entire experimental phase. Urinary nitrogen excretions remained fairly constant for both groups during the training and heavy physical activity periods. Nitrogen balances were positive exclusive or inclusive of the daily sweat nitrogen losses showing nitrogen retention. The essentially unchanged blood hemoglobin and serum protein levels showed the control group was receiving an adeuqate protein intake to maintain nitrogen equilibrium, under conditions of fairly heavy physical activity. Although others may have suggested some compensatory reductions in the urinary excretion of nitrogen under conditions of profuse sweating, our data have not supported these conclusions. It appears that sweat losses of nutrients become relevant in determining requirements and will increase in importance as sweat rates are increased. The data again demonstrate that the nutrient losses during profuse sweating constitute and error that could seriously invalidate the accuracy of metabolic balance studies.