Iron metabolism and "sports anemia". I. A study of several iron parameters in elite runners with differences in iron status.

Several reports have suggested that iron deficiency might explain "sports anemia" especially in long distance runners. The present study was made to further study the iron metabolism in runners as the proposed cause of "sports anemia" is abstruse considering the good iron nutrition in these athletes. Based on a screening of 43 elite male runners, using bone marrow hemosiderin, serum ferritin and transferrin saturation, two groups of subjects were selected for a very extensive study on iron metabolism. In group 1 (n = 5) iron depletion was suggested in at least one of the screening studies. In group 2 (n = 7) at least one test strongly indicated good iron repletion. This experimental design was chosen to obtain two groups with similar body composition and exercise load but different iron metabolism. The studies comprised determinations of red cell and plasma volumes, plasma iron turnover and red cell incorporation of radioiron, red cell indices, plasma iron and transferrin, red cell protoporphyrin, serum ferritin, serum haptoglobin, urinary iron losses, iron absorption, bone marrow hemosiderin, dietary intake of energy and nutrients and a Desferal test. Pooling the results together it was obvious that none of the subjects were truly iron-deficient. A few occasional findings suggesting low iron stores cannot be satisfactorily explained and indicate that further studies are needed.