Increased Hepcidin Levels During a Period of High Training Load Do Not Alter Iron Status in Male Elite Junior Rowers

Abstract

The liver-derived hormone hepcidin plays a key role in iron metabolism by mediating the degradation of the iron export protein ferroportin 1 (FPN1). Circulating levels of hepcidin and the iron storage protein ferritin are elevated during the recovery period after acute endurance exercise, which can be interpreted as an acute phase reaction to intense exercise with far-reaching consequences for iron metabolism and homeostasis. Since absolute and functional iron deficiency (ID) potentially lead to a loss of performance and well-being, it is surprising that the cumulative effects of training stress on hepcidin levels and its interplay with cellular iron availability are not well described. Therefore, the aim of this study was to determine serum levels of hepcidin at six time points during a 4-week training camp of junior world elite rowers preparing for the world championships and to relate the alterations in training load to overall iron status determined by serum ferritin, transferrin, iron, and soluble transferrin receptor (sTfR). Serum hepcidin levels increased significantly (p = 0.02) during the initial increase in training load (23.24 ± 2.43 ng/ml) at day 7 compared to the start of training camp (11.47 ± 3.92 ng/ml) and turned back on day 13 (09.51 ± 3.59 ng/ml) already, meeting well the entrance level of hepcidin at day 0. Serum ferritin was significantly higher at day 7 compared to all other timepoints with exception of the subsequent time point at day 13 reflecting well the time course pattern of hepcidin. Non-significant changes between training phases were found for serum iron, transferrin, and sTfR levels as well as for transferrin saturation, and ferritin-index (sTfR/log ferritin). Our findings indicate that hepcidin as well as ferritin, both representing acute phase proteins, are sensitive to initial increases in training load. Erythropoiesis was unaffected by iron compartmentalization through hepcidin. We conclude that hepcidin is sensitive to rigorous changes in training load in junior world elite rowers without causing short-term alterations in functional iron homeostasis.

Differences in Immune Response During Competition and Preparation Phase in Elite Rowers

“…Also in rowers, acute inflammatory responses to training are associated with decreased aerobic performance (VO 2 max and maximal aerobic power; Jürimäe et al, 2016). In line with that we previously showed that hepcidin and ferritin, both representing acute-phase proteins, are sensitive to initial increases in training load after seven days during a training camp (Zügel et al, 2019). Also, in the present study, we found slightly increased ferritin levels during COMP, which were not associated with significantly increased IL-6 levels.…”

Effects of antioxidant supplementation on oxidative stress balance in young footballers- a randomized double-blind trial

“…This may reflect the players’ adaptation to the applied exercise load. Zügel et al [ 49 ] analysed the cumulative effect of training stress in highly qualified athletes practising rowing, focusing on hepcidin and parameters related to iron management. The authors showed that the levels of hepcidin and ferritin, acute-phase proteins, were a sensitive indicator of changes in the training load (exercise volume and intensity).…”

Effects of antioxidant supplementation on oxidative stress balance in young footballers– a randomized double-blind trial

“…Zügel et al analysed the cumulative effect of training stress in highly quali ed athletes practising rowing on the level of hepcidin and its impact on parameters related to iron management. They showed that the levels of hepcidin and ferritin as acute-phase proteins were a sensitive indicator of changes in training loads (increase in volume and intensity of exercise) [44]. In the above study, football players were subjected to the same training loads throughout the entire study period, which probably explains the lack of statistically signi cant differences in the levels of hepcidin and ferritin .…”