Inorganic Iron Supplementation Rescues Hematological Insufficiency Even Under Intense Exercise Training in a Mouse Model of Iron Deficiency with Anemia.

Iron deficiency anemia (IDA) due to malnutrition and/or blood loss is a common condition, especially in women of reproductive age. Intense exercise can induce anemia via an inflammatory response, but whether intense exercise affects the efficacy of iron supplementation to treat IDA is unclear. Here, we show in a mouse model of IDA that acute intense swimming increased IL-6 levels in the blood, but did not affect the maximum elevation of plasma iron following oral administration of 0.5 mg/kg Bw iron. However, compared with the control group without intense exercise, acute intense swimming was associated with a significant decrease in plasma iron 2 and 4 h after iron loading that could be attributed to rapid iron absorption in peripheral tissues. In the chronic experiment, IDA mice administered 0.36, 1.06, or 3.2 mg/kg Bw iron per day that were subjected to 11 intense swimming sessions over 3 weeks showed significantly decreased recovery levels for hemoglobin and red blood cell count during the early phase of the experimental period. At the end of the experimental period, significant, dose-dependent effects of iron, but not the main effect of intense exercise, were seen for recovery of hemoglobin and red blood cell counts, consistent with the acute exercise study. These results suggested that intense exercise in the presence of IDA does not inhibit iron absorption from the gastrointestinal tract and that iron supplementation can enhance the recovery process even after intense exercise.