Decreased Cellularity and Hemosiderin of the Bone Marrow in Healthy and Overtrained Competitive Distance Runners.

In brief: Fourteen healthy and seven overtrained competitive distance runners were studied to investigate the frequency and significance of decreased bone marrow cellularity (BMC) and bone marrow hemosiderin (BMH) and the relationship between BMC, BMH, hemoglobin, and serum ferritin levels. Bone marrow hypocellularity or mild hypocellularity was found in 54% of the healthy male runners. Hypocellular marrow was found in 66% of the overtrained male runners. Absence or severe reduction of BMH granules was found in all runners. The mean hemoglobin and serum ferritin values were normal but somewhat lower than those of a control group. There may be a direct relationship between decreased BMC and years of running.