Hematological, electrolyte, and biochemical alterations after a 100-km run.

Seven well-trained male long-distance runners were studied during a 100-km road race. Hematologic parameters, plasma electrolytes, glucose, lactate, urea, and creatinine content in plasma and the activity of the enzymes gamma-glutamyltransferase and creatinine kinase were determined before and after the race. A slight increase in hematocrit was found after the race, although the red blood cell count and hemoglobin concentration remained unchanged. Further, a significant rise in the number of white blood cells, lymphocytes, and neutrophils was found after the race. Postrun concentrations of plasma sodium and potassium increased significantly from 142 +/- 7 to 161 +/- 7 mmol.L-1, and from 4.22 +/- 0.37 to 5.15 +/- 0.46 mmol.L-1 (p < 0.05), respectively. Plasma concentrations of lactate (1.29 +/- 0.31 vs. 3.57 +/- 1.22 mmol.L-1), urea (6.09 +/- 1.0 vs. 8.35 +/- 1.35 mmol.L-1), creatinine (73.4 +/- 3.5 vs. 117.6 +/- 19.4 mumol.L-1), plasma creatine kinase (91.1 +/- 25.1 vs. 2843 +/- 2341 IU.L-1), and gamma-glutamyltransferase (20.28 +/- 1.88 vs. 24.14 +/- 4.09 IU .L-1) increased significantly (p < 0.05) after the run. It was concluded that during ultralong-distance races, acute renal dysfunction and muscle damage could contribute to the observed hypernatremia and hyperkalemia.