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

Amy Woods, Laura GARVICAN, Philo Saunders, Greg Lovell, David Hughes, Ruth Fazakerley, Bev Anderson, Christopher Gore, Kevin THOMPSON

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    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 μgL21 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 106400 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).

    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.

    Results: Serum ferritin increased in IRON only (Week 0: 62.8621.9, Week 4: 128.1646.6 μgL21; p = 0.002) and remained elevated two weeks after the final injection (127.0666.3 μgL21, 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: 625.6655.5 s vs. 625.4652.7 s; PLACEBO: 624.8647.2 s vs. 639.1659.7 s); but IRON reduced their average time for the 106400 m training session at week 2 (Week 0: 78.066.6 s, Week 2: 77.266.3; ES-0.20, p = 0.004).

    Original languageEnglish
    Article numbere108042
    Pages (from-to)1-11
    Number of pages11
    JournalPLoS One
    Issue number9
    Publication statusPublished - 23 Sept 2014


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