The effects of exercise training and iron intake on iron metabolism in adult female rats were investigated. Adult female Sprague-Dawley rats were assigned to either an exercise (E) or sedentary (S) group and fed either a diet containing 9 ppm (9) of dietary iron (low iron level), or 40 ppm (40) of iron (a level slightly above the National Research Council recommendations). The exercise animals were subjected to a program of swimming, 5 days/week, over a 6- week period. Total food intake and final body weight were similar between the E and S groups. In both 40-E and 9-E animals, concentration of serum iron was significantly (P<0.05) lower while total iron binding capacity was significantly elevated, when compared to sedentary counterparts. Saturation of transferrin was significantly reduced in the 9-E group. Liver and spleen weights did not differ but significant increases in cardiac weights were noted in both E groups. Gastrocnemius muscle weights were similar in both E groups and 9-S, but significantly lower in the 40-S group. In organ tissues, liver iron concentration was significantly reduced in the 9-E animals, while spleen iron level was highest in the 40-E group. Cardiac iron concentration was significantly reduced in both E and low iron diet groups while levels of iron in gastrocnemius muscle did not differ among experimental groups. In both groups of exercised rats, bone marrow iron was significantly lower when compared to sedentary animals. In response to exercise training, an increase in skeletal muscle citrate synthase activity was observed in both E groups. This study suggests that exercise affects various parameters of iron metabolism. Regardless of iron intake, physical training appeared to alter distribution of iron stores, that may be associated with alterations of hematological iron transport and iron-containing proteins. The Combination of a low iron intake and intense exercise training appeared to enhance early characteristics of a latent iron deficiency. / Ph. D.