Effect of resistance exercise on iron status in moderately iron-deficient rats.

Resistance exercise increases heme synthesis in the bone marrow, but it does not improve the hemoglobin status in severe iron-deficient rats on a diet containing less than 5 mg iron/kg. The current study investigated whether resistance exercise could mitigate hemoglobin status via increasing heme synthesis in moderately iron-deficient rats. Male 4-week-old Sprague-Dawley rats were fed an iron-deficient diet containing 12 mg iron/kg for 3 weeks. The rats were divided into two groups: a sedentary (S) group (n = 7) or an exercise (E) group (n = 7). The rats in the E group performed a climbing exercise (5 min × 6 sets/day, 3 days/week). The aminolevulinic acid dehydratase activity, hematocrit, and hemoglobin tended to be higher in group E than S. The iron content in the flexor hallucis longus muscle was significantly higher in E than S, whereas the content in the liver, spleen, kidney, and heart did not significantly differ between the groups. Therefore, resistance exercise appears to improve hemoglobin via increasing heme synthesis in the bone marrow in moderately iron-deficient rats.