Not only the optimum prescription for prevention but also the mechanism of the sports anemia which is induced during physical training are still unclear. Therefore, the current study was carried out to investigate these questions. Mild anemia was observed in elite distance runners. The data suggest that hemolysis and iron deficiency might be major causes of the anemia. In response to a single bout of exhaustive exercise on a motor-driven treadmill, decrease in haptoglobin and elevation of serum lactate dehydrogenase level (both H and M subunits) were induced suggesting an occurrence of hemolysis. Serum myoglobin also tended to increase. Hemoconcentration during exercise was accompanied by a significant elevation of both platelet and tissue plasminogen activator levels suggesting that both blood coagulation and fibrinolysis were activated. Increased fibrinolysis, which helps to reduce the vascular resistance, may be closely related to the training-induced hemodilution. In general, the data in the current study may suggest that mild decrease in hemoglobin concentration caused by training may not be the limiting factor of the work performance. But it is definitely important to examine the cause of the decreased hemoglobin level precisely and perform a suitable treatment, if necessary.

DESCENTE SPORTS SCIENCE Vol.10/THE DESCENTE AND ISHIMOTO MEMORIAL FOUNDATION FOR THE PROMOTION SPORTS SCIENCE