Effect of Intravenous Iron Therapy on Exercise Performance, Fatigue Scores and Mood States in Iron-deficient Recreationally Active Females of Reproductive Age: a Double-blind, Randomised Control Trial (IRONWOMAN Trial)

Objectives: Non-anaemic iron deficiency (IDNA) is highly prevalent in exercising females. Although iron therapy can be used to correct this issue, its impact on exercise performance is equivocal. Our aim was to assess the efficacy of intravenous iron therapy on exercise performance, fatigue, mood states, and quality of life in recreationally active IDNA females of reproductive age.

Methods: Twenty-six recreationally active IDNA females were randomised to either an intravenous iron treatment (IRON) group or placebo (PLA). Prior to, 4 days and 4 weeks following intervention, participants completed a variety of assessments to determine changes in exercise performance, haemoglobin mass, blood iron status and haematology, fatigue levels, mood states and quality of life.

Results: Intravenous iron therapy significantly improved serum ferritin, serum iron and transferrin saturation (p<0.05), with a highly variable individual response. No differences were observed between groups' peak oxygen consumption (V̇O), lactate threshold or haemoglobin mass. Running economy improved in IRON from baseline to 4 weeks (p<0.05), which was also different to PLA at 4 weeks (p<0.05). Fatigue scores improved in IRON but not PLA after 4 weeks (p<0.05). Mood states and quality of life remained unchanged in both groups over the trial.

Conclusion: In recreationally active IDNA females, intravenous iron therapy corrects iron status and improves both exercise economy and fatigue scores after 4 weeks.

Trial Registration Number: ACTRN12620001357943.