Effect of 12 weeks of strenuous physical training on hematological changes

It is well known that sports and physical exercise affect the hemoglobin (Hb) concentrations; however, the factors affecting the hematological changes after intense exercise are still not fully elucidated. In the present study, we examined the hematological and biochemical parameters of nine young male soldiers participating in a 12-week ranger training program. The platelet counts before the training showed a strong inverse correlation with the Hb concentrations after the training (r = -0.829, p < 0.01). Furthermore, the Hb concentrations of the subjects whose platelet counts were more than 25.0 x 10(4)/mu L decreased significantly after the training (p < 0.05). Our findings suggest that an association exists between high platelet counts even within the normal range before strenuous physical training and the risk of a subsequent decrease in the Hb concentrations.