Evaluation of iron metabolism indices and their relation with physical work capacity in athletes.

OBJECTIVE To evaluate the relation between iron status and physical working capacity, and to assess the effect of oral iron treatment on these variables, in athletes with borderline iron status. METHODS Blood haemoglobin (Hb), packed cell volume (PCV), red blood cell count (RBC), serum iron, total iron binding capacity (TIBC), and ferritin determinations were compared in 71 male and 18 female athletes participating in various sports and in matched male (n = 11) and female (n = 8) controls. The first aim was to assess the relations between these variables and performance in a physical work capacity test (PWC170). Oral iron treatment (175-350 mg ferrous fumarate daily) was provided for three weeks to six male and five female athletes with borderline Hb concentrations, to determine the effects of such treatment on both iron status and performance. RESULTS Among females, handball players had the lowest serum ferritin concentrations (P < 0.05), the highest TIBC values, and lowest PWC170 scores (P < 0.01); runners had the highest ferritin concentrations and PWC170 scores (P < 0.01). There were significant correlations (P < 0.01) between PWC170 and PCV, serum ferritin, and transferrin saturation of female athletes. Hb, serum iron, serum ferritin, and transferrin saturation increased with iron treatment in both males (P < 0.01) and females (P < 0.05). CONCLUSIONS Serum ferritin determination may prove a valuable addition to the screening of athletes and may indicate the need for iron treatment, even though a causal effect on improvement of work capacity may not be present.