D-Lactate concentrations in blood, urine and sweat before and after exercise

SummaryThe purpose of this study was to investigate changes in the concentrations of D-lactate, L-lactate, pyruvate and methylglyoxal (MG) in body fluids after exercise. Eight untrained male students and five male students who were boat club members engaged in the exercise. Each subject performed runs of short and long duration. Compared to pre-exercise values plasma concentrations of D-lactate, L-lactate and pyruvate increased after running; in trained men by 3.6, 5.0, 3.4 times after short runs and by 1.5, 4.6, 2.0 times after long runs, and in untrained men by 3.0, 12.0, 1.6 times after short runs and 2.5, 5.6, 1.6 times after long runs, respectively. In all cases, the increase of L-lactate was always higher than that of D-lactate after running. The MG contents in red blood cells decreased markedly after running, especially in the untrained students. After short runs the MG concentration had decreased to 13% in the untrained men and 30% in the trained men, and after long runs the concentration had decreased to 41% in the untrained and 60% in the trained men. The MG in plasma and red blood cells appeared to have been utilized during relatively anaerobic exercise, especially by the untrained subjects. The D-lactate and related substances were also determined in urine, but the concentration of these substances showed no relationship to exercise. The D-lactate concentration in sweat samples tripled after short periods of running but the relative concentration to sodium ion concentration was not altered. The L-lactate, pyruvate, and MG concentrations in sweat increased after short duration running but their concentrations relative to sodium ion concentration were decreased significantly.