Four Weeks of IV Iron Supplementation Reduces Perceived Fatigue and Mood Disturbance in Distance Runners

Purpose

To determine the effect of intravenous iron supplementation on performance, fatigue and overall mood in runners without clinical iron deficiency.

Methods

Fourteen distance runners with serum ferritin 30–100 µg·L−1 were randomly assigned to receive three blinded injections of intravenous ferric-carboxymaltose (2 ml, 100 mg, IRON) or normal saline (PLACEBO) over four weeks (weeks 0, 2, 4). Athletes performed a 3,000 m time trial and 10×400 m monitored training session on consecutive days at week 0 and again following each injection. Hemoglobin mass (Hbmass) was assessed via carbon monoxide rebreathing at weeks 0 and 6. Fatigue and mood were determined bi-weekly until week 6 via Total Fatigue Score (TFS) and Total Mood Disturbance (TMD) using the Brief Fatigue Inventory and Brunel Mood Scale. Data were analyzed using magnitude-based inferences, based on the unequal variances t-statistic and Cohen's Effect sizes (ES).

Results

Serum ferritin increased in IRON only (Week 0: 62.8±21.9, Week 4: 128.1±46.6 µg·L−1; p = 0.002) and remained elevated two weeks after the final injection (127.0±66.3 µg·L−1, p = 0.01), without significant changes in Hbmass. Supplementation had a moderate effect on TMD of IRON (ES -0.77) with scores at week 6 lower than PLACEBO (ES -1.58, p = 0.02). Similarly, at week 6, TFS was significantly improved in IRON vs. PLACEBO (ES –1.54, p = 0.05). There were no significant improvements in 3,000 m time in either group (Week 0 vs. Week 4; Iron: 625.6±55.5 s vs. 625.4±52.7 s; PLACEBO: 624.8±47.2 s vs. 639.1±59.7 s); but IRON reduced their average time for the 10×400 m training session at week 2 (Week 0: 78.0±6.6 s, Week 2: 77.2±6.3; ES–0.20, p = 0.004).

Conclusion

During 6 weeks of training, intravenous iron supplementation improved perceived fatigue and mood of trained athletes with no clinical iron deficiency, without concurrent improvements in oxygen transport capacity or performance.

Citation: Woods A, Garvican-Lewis LA, Saunders PU, Lovell G, Hughes D, Fazakerley R, et al. (2014) Four Weeks of IV Iron Supplementation Reduces Perceived Fatigue and Mood Disturbance in Distance Runners. PLoS ONE 9(9):
e108042.

https://doi.org/10.1371/journal.pone.0108042

Editor: Stephen E. Alway, West Virginia University School of Medicine, United States of America

Received: March 31, 2014; Accepted: August 25, 2014; Published: September 23, 2014

Copyright: © 2014 Woods et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Data Availability: The authors confirm that, for approved reasons, some access restrictions apply to the data underlying the findings. The individual data cannot be made available in the manuscript, the supplemental files, or a public repository for ethical and privacy reasons because the data were collected on human subjects. De-identified data will be made available to all interested researchers upon request. Requests can be made to the corresponding author (Dr Laura Garvican-Lewis) or the secretary of the Australian Institute of Sport Human Ethics Committee (Ms Helene Rushby).

Funding: Funding for the study was received from a University of Canberra grant for Post-doctoral Fellowship Research. The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Competing interests: The authors have declared that no competing interests exist.

Intravenous iron supplementation improved perceived fatigue and mood in trained athletes without clinical iron deficiency.