| The effect of participation in an intercollegiate field hockey season in the iron status of women athletes was studied over two seasons of play. Thirteen athletes and thirteen controls were studied in the first season; sixteen athletes and sixteen controls, in the second season. Subjects were measured pre- and postseason for serum ferritin, hemoglobin, hematocrit, free erythrocyte protporphyrin, iron and vitamin C intake and exercise heart rate during a treadmill walking test. Information on menstrual cycle, i.e., day of cycle, length of cycle and amount of flow described as light, medium, or heavy, was recorded at the time blood samples were taken.;A training effect on the athletes was found according to the significantly decreased submaximal heart rates (measured in the first season only) when athletes were compared to controls. A significant decrease (p < .05) in iron stores 30 to 19 ng/ml), as measured by serum ferritin, was found in the athletes as compared to the controls (30 to 24 ng/ml) in the second season but not in the first. Serum ferritin changes in the first season were a decrease from 24 to 23 ng/ml in athletes and an increase from 26 to 28 ng/ml in the controls. In the eight athletes participating in both years, the year and the interaction of year with training did not have a significant effect on serum ferritin measures. Serum ferritin levels decreased over both years from 22 to 16 ng/ml (p = .06) for these eight women.;Hemoglobin and hematocrit increased significantly in the athletes as compared to the controls in the second season. Iron intake averaged 13 mg/day in all subjects. Neither iron nor vitamin C intake differed significantly between athletes and controls over either year. Changes in free erythrocyte protoporphyrin (measured in the second season only) did not differ significantly between the two groups.;For the entire sample of subjects none of the other measured variables, i.e., blood parameters, dietary intake, or submaximal heart rates, correlated significantly with the serum ferritin measures, except the vitamin C intake (r = .48) with the postseason serum ferritin. Menstrual cycle data did not correlate significantly with serum ferritin.;The mean daily iron intake of these athletes (10 ng/day) appeared to be insufficient to meet the demand from iron accompanying the physical training. Iron stores of athletes, after participating in several years of college play, were frequently between 10 and 20 ng/ml. Evidence from this study partially supports the hypothesis of an overall decrease in the athletes' serum ferritin levels after a season of field hockey as compared to little change in serum ferritin of inactive women. |
