RESUMO
Forty-two female college students underwent fitness-type exercise over a 13 week period. The students exercised an average of two times a week for 30 minute periods at 50% levels of VO2 . max. Iron status and hematological laboratory data were monitored at three points in time; at the initiation of exercise, at the termination of exercise and 3 months later. Serum ferritin levels in a third of the students were lower than 12ng/ml. Red blood cell counts decreased during exercise, and returned to the pre-exercise levels 3 months later. The number of circulatory reticulocytes and mean corpuscular hemoglobin concentration were increased significantly after the exercise and the effects were still observed 3 months later, independent of the iron status. In the lower ferritin group, erythropoietin levels decreased significantly during the post-exercise period. The average serum ferritin levels while showing no significant changes during exercise, increased significantly during the post-exercise period, in the normal ferritin group. We discussed possible mechanisms, among them iron metabolism, by which physical training may facilitate erythropoiesis. However, no definite conclusions have been reached.
