[Study of variations in hematologic parameters in rugby players undergoing physical training at a high altitude]

Thirty-three well-trained rugby players, ranging in age from 18 to 30 years, were studied during basal training for one year. Peripheral blood parameters and iron metabolism indices were investigated before, during and at the end of the season. The hematologic status showed no substantial changes with respect to physical activity even if considered by age and team-role. However, a significant reduction (P less than 0.001) in RBC count, hemoglobin, hematocrit, serum iron, plasma transferrin and ferritin, was observed when compared with those obtained from a group of healthy untrained controls. Since the decrease in serum iron and ferritin concentrations was significant so as to justify a similar reduction in Hb and Ht values, two pathogenic mechanisms must be considered: e.g., a moderate hemodilution secondary to plasma expansion combined with a decrease in iron stores caused by chronic iron loss through feces, profound sweat and urine. The present study demonstrates that mild anemia (sports anemia) may develop in well-trained rugby players with heavy physical work load, due to increased plasma volume with a relative thinning of RBCs. This pseudo-anemic condition is associated with a reduction in iron stores which can lead to a true iron-deficiency anemia. A yearly blood test and, if necessary, iron supplementation could prevent this condition.