[Hematologic changes induced by exertion during a long-distance race].

PURPOSE: To evaluate the haematological changes induced by a long-distance race in well trained runners. PATIENTS AND METHODS: The haematological changes presented by 17 runners (15 men and 2 women) were assessed in a 6-hour race. For this purpose samples were examined before the race, 2 hours later, 4 hours later, at the end of the race, and 4 days after the trial. RESULTS: Haemoglobin rates, as well as leucocyte, neutrophil, monocyte and platelet counts were increased, probably due to decreased plasma volume. Haemolytic traits were seen as well, namely, increased reticulocyte count and decreased haptoglobin. High transferrin-transport capability and serum B12 levels were also present. Mild haematuria was found without any haemosiderinuria, siderinuria or haemoglobinuria. All these changes recovered in the post-race study. CONCLUSION: Changes in the major haematologic values are present during long-distance races, some of them due to haemoconcentration. Leucocytosis, haemolysis and haematuria are noteworthy, and these findings must be borne in mind when evaluating the health of runners.