Interactions of iron deficiency and exercise training in male Sprague-Dawley rats: ferrokinetics and hematology

Ferrokinetic and hematologic studies were performed using adult male Sprague-Dawley rats to determine if 12 wk of exercise training alters the delivery of iron to the red blood cell (RBC) mass, the severity of the anemia or the maximal exercise performance of moderately iron-deficient animals. Forty rats were assigned to either iron-deficient (ID) or control (CN) diets, and further subdivided into sedentary (SD) and exercised (EX) groups. Exercised groups were trained on a treadmill, at a 15% grade, 65% VO2max, for 90 min/d, 4 d/wk. After 12 wk of exercise training and dietary iron deficiency, the final body weight of IDEX rats was 90.5% that of IDSD rats. Fractional plasma iron clearance in IDEX rats was 86% of that in IDSD rats (3.32 vs. 2.85%/min). Exercise training failed to increase absolute VO2max (ml/min) or change hemoglobin concentration in iron-deficient rats. Resting oxygen consumption in IDEX rats was 116% that in IDSD rats (42.8 vs. 32.5 ml.kg-1.min-1, P less than 0.05). We conclude that exercise training and iron deficiency interact to alter iron physiology in exercised, iron-deficient animals. This interaction affects the kinetic behavior of plasma iron, growth and basal oxygen consumption.