KLINGSHIRN, L. A., R. R. PATE, S. P. BOURQUE, J. M. DAVIS, and R. G. SARGENT. Effect of iron supplementation on endurance capacity in iron-depleted female runners. Med. Sci. Sports Exerc., Vol. 24, No. 7, pp. 819-824, 1992. The purpose of this investigation was to examine the effects of oral iron supplementation on endurance performance in initially iron-depleted, nonanemic female distance runners. Eighteen iron-depleted (serum ferritin <=20 ng[middle dot]ml-1, hemoglobin >= 12 g[middle dot]dl-1) women (22-39 yr) performed a [latin capital V with dot above]O2max test and an endurance run to exhaustion. Subjects were pair-matched on the basis of endurance time and then randomly assigned to an iron supplement or a placebo group. Following supplementation, the iron group had a significantly higher (P = 0.03) mean serum ferritin concentration (23.4 vs 15.7[middle dot]ng-ml-1) and lower (P = 0.04) mean total iron-binding capacity than the placebo group. Both groups increased their time to exhaustion (25.5% and 22.2% for the iron and placebo groups, respectively) but were not significantly different (P = 0.72) from each other. There were also no differences (P> 0.05) between the groups with respect to lactate concentrations and physiological measures taken during the two exercise tests. The results of this study suggest that 8 wk of oral iron supplementation improves iron status in iron-depleted female distance runners, but does not enhance endurance capacity.
(C)1992The American College of Sports Medicine