Impact of a single swimming session on inflammatory response and iron homeostasis in adolescent female athletes during the luteal phase

The intensity and duration of physical activity significantly influence hepcidin levels, a vital hormone that manages iron balance. Its increase is associated with exercise-induced inflammation, particularly involving interleukin-6. This study explored the effect of a single swimming session on specific markers of inflammation and iron metabolism in young female athletes during the luteal phase of their menstrual cycle. Eighteen competitive swimmers (13.5 ± 1.2 years old) completed three distances (800 m, 200 m, and 50 m) in the shortest possible time with active recovery periods between segments. Venous blood samples were taken before exercise, immediately afterward, and after 3 h of recovery. Swimming has caused a significant increase in lactate and hypoxanthine, indicating a high level of exercise intensity. While no significant changes in hepcidin or IL-6 were observed at 3 h post-exercise, later time points were not assessed. Immediately following exercise, transferrin levels rose, while total iron-binding capacity declined. Despite the absence of an inflammatory response, mild adaptive changes were observed in selected indicators of iron metabolism. Alterations in concentrations of iron, erythroferrone, ferritin, transferrin, and red blood cell parameters suggest that responses within the iron regulatory system may occur independently of hepcidin activity, with notable contributions from ferritin, transferrin, and mechanisms related to erythropoietic activity.