Plasma urea, creatinine, uric acid, albumin, and total protein concentrations before and after 15-, 25-, and 42-km contests.

One hundred fourteen volunteers (34 +/- 8 years) took part in an endurance training study to be completed after 18-20 months with a marathon. Ultimately, 60 males and 18 females achieved that goal. The training program, carefully supervised, was divided into three periods with a maximum of 45, 70, and 110 km/week training volume and concluded with contests of 15, 25, and 42.2 km, respectively. The competitive distance always exceeded the maximal distance covered in any previous training session. Three days before and 3 and 5 days after each race 35 subjects were selected to perform a progressive treadmill test and the remaining subjects participated in field tests of 400 and 1000 m. Before and after three contests of 15, 25, and 42.195 km the plasma concentration of urea, creatinine, uric acid, albumin, and total protein were determined. Both sexes demonstrated an increase of the plasma concentrations of urea, creatinine, and uric acid after the contests. Plasma albumin concentration decreased 2 days after the contests and total protein did not change. In females the decrease of the elevated plasma urea concentration after the marathon from the 1st day to the 3rd day post-exercise was faster than in males. The increase of plasma creatinine and uric acid concentrations were hardly dependent on the contest's distance.