Renal protein excretion after exercise in man.

Thirteen men were submitted to graded exhaustive cycle exercise to determine the kinetics of proteinuria in the recovery period. Venous blood samples were analysed for haematocrit, lactate, creatinine, total protein and albumin for 1 h following exercise. Urine samples were collected during a 3-h recovery period. Total protein, albumin, and creatinine levels were determined for these samples. Total protein and albumin urinary excretion increased to 581 and 315 micrograms min-1, respectively, at the end of the 1st h of recovery as compared to 42 and 15 micrograms.min-1 for resting values. Plasma volume returned to pre-exercise levels between 30 and 60 min after cessation of exercise, while urinary total protein and albumin content still remained above the resting values for the following 2 h. Both post-exercise urinary total protein and albumin excretion followed a logarithmic decline with the same half-life of 54 min, thus requiring about 4 h to regain resting values. The reduction of plasma volume and the degree of dehydration do not seem to be involved in the process. The present study indicates the delayed recovery of protein handling by the kidney, as compared with other biochemical parameters, and provides accurate information on the kinetics of post-exercise proteinuria.