Abstract

Several reports have suggested that trained runners have suboptimal hemoglobin and hematocrit levels, and may be prone to iron deficiency. In this study a hematological comparison was performed between 41 trained male runners and 36 male controls. The RBC count, Hb, PCV, transferrin saturation and serum ferritin values were lower in runners than in the controls. These values were not low enough to indicate a true iron deficiency. The higher MCHC, serum iron and TIBC values with normal reticulocyte count support the conclusion of a normal iron supply. Lower serum haptoglobin values in runners indicated an increased resting intravascular hemolysis. Since the Hb-Hp complex formed is taken up and metabolized by hepatocytes, this implies that there is a shift in red cell catabolism in runners from the RES cells to hepatocytes. This shift may explain the finding of lower serum ferritin levels, which reflect only the size of the RES iron stores. However the release in the plasma iron pool of hemoglobin iron from hepatocytes is much slower than from RES cells. This may lead to slower iron availability for essential biological functions. In runners, hematological monitoring is necessary to distinguish the subjects who are at a risk of true iron deficiency; iron supplementation should be restricted to the latter subjects only. Verf.-Referat