[Decreased bone marrow cellularity and hemosiderin in normal and overtrained runners].

The frequency and significance of decreased bone marrow cellularity (BMC) and bone marrow hemosiderin (BMH), and their possible relations to hemoglobin, iron, iron saturation and serum ferritin levels, were studied in 18 normally trained and 18 overtrained competitive distance runners. Decreased BMC was more pronounced in the overtrained runners: mild to moderate hypocellular marrow was found in 25% of them, and severe hypocellularity in another 25%, as compared to 18% and 3.5%, respectively, in the healthy runners. Increased erythrocyte mean corpuscular volume (greater than 95 mu 3) was found in 24% of the runners, but in only 3.5% of the controls. Decreased BMH was found in both the overtrained (1.3 +/- 2.0 hemosiderin granules per 100 normoblasts) and the controls (1.5 +/- 1.9 granules). There were no significant differences in levels of hemoglobin, mean corpuscular volume and serum iron, iron saturation and ferritin. The decreased BMH in the face of normal hemoglobin and serum iron and ferritin suggests that as a group, competitive distance runners do not suffer from overt iron deficiency but that iron might be stored differently, with a lesser proportion in the bone marrow. The more pronounced decrease in BMH of overtrained distance runners may indicate a possible relationship, and decreased BMC may identify runners who may be becoming overtrained.