The effects of exercise and dietary iron on iron status in 19 month old adult female rats

Abstract

This study investigated the effects of exercise and dietary iron on iron status in 19-month-old female rats. Fifty-seven female Sprague-Dawley rats were randomly assigned to one of five experimental groups: baseline (BL); iron sufficient-exercise (HE); iron sufficient-sedentary (HS); moderate iron deficient- exercise (LE) and moderate iron deficient-sedentary (LS). The six-week exercise protocol involved swimming 5 days/week beginning at 10 minutes/day and ending at I hour/day by the fifth and sixth week. The results indicated a significant effect of exercise on food intake and on body weight, with higher levels of intake and body weight in the LS group compared to the exercised groups. Soleus muscle weight was significantly lower than BL in the HS, LE and LS groups. Gastrocnemius muscle weight was significantly higher in the HS than in the LE group. Cardiac weights were comparable in the1LE, LS and HE groups but significantly higher than the HS group. Cardiac citrate synthase activities were not significantly different among the groups. No significant effects of diet, activity or an interaction effect were noted on hemoglobin, serum iron and total iron binding capacity. Hematocrit concentrations demonstrated a significant effect of activity, with elevated levels in the exercised groups compared with baseline. Serum iron levels were significantly lower in the LE group than the iron sufficient groups. The TIBC levels were significantly lower in the LE group than in the baseline. Liver iron concentrations showed a significant effect of diet, with higher concentrations in the iron sufficient groups compared to the LE group. Iron concentrations in the spleen and soleus muscle were unchanged however spleen iron concentrations were significantly higher in BL than in the experimental groups. Exercise had a significant effect on the gastrocnemius muscle with lower iron concentrations in the sedentary groups than in the exercised groups.

These results suggest a trend towards redistribution of iron stores as a result of exercise as evidenced by alterations in iron concentrations in some tissues and a trend towards elevated hemoglobin and hematocrit levels. Thus, dietary iron deficiency and exercise adversely affected various components of iron metabolism in the aged female rat although it was not manifested as iron deficiency.