Single versus Split Dose of Iron Optimizes Haemoglobin Mass Gains at 2106 m Altitude

PURPOSE To determine if a single versus a split equivalent daily dose of elemental iron was superior for haemoglobin mass (Hbmass) gains at altitude, while minimizing gastrointestinal (GI) discomfort. METHODS Twenty-four elite runners attended a 3.1 ± 0.3 week training camp (Flagstaff, AZ; 2106 m). A two-group design, randomized and stratified to baseline Hbmass, sex and ferritin (>30 μ/L), was implemented daily as: 1) single dose of 1 x 200 mg (PM only, SINGLE) vs; 2) split dose of 2 x 100 mg (AM & PM; SPLIT) elemental iron (ferrous fumarate). Hbmass and venipuncture assessments were completed upon arrival and departure (± 2 days) from camp for ferritin, hepcidin and erythroferrone (ERFE) concentrations. Validated food frequency (FFQ), GI-distress, menstrual blood loss (MBL) and training questionnaires were implemented throughout. Univariate analysis was used to compare Hbmass; with baseline ferritin, dietary iron intake, MBL and training volume used as covariates. RESULTS Both conditions increased Hbmass from baseline (p0.05). CONCLUSION A single nightly 200 mg dose of elemental iron was superior to a split dose for optimizing Hbmass changes at altitude in runners over a ~3 week training camp. Corresponding Author: Rebecca Hall, University of the Sunshine Coast, School of Health and Sports Sciences, 90 Sippy Downs Dr, Sippy Downs, QLD 4556, Australia. +61 (0)407 404 333; RCH010@student.usc.edu.au Funding, logistical support and testing for this research was gratefully received from B2Ten, Athletics Canada, the Canadian Sports Institute Pacific, University of Western Australia, Western Australian Institute of Sport and the University of California at Los Angeles. The authors of this study declare that results are presented honestly, clearly and without fabrication, falsification or inappropriate data manipulation. Results of this study do not constitute endorsement by ACSM. CONFLICTS OF INTEREST: E.N. is a stockholder and consultant for Intrinsic LifeSciences and Silarus Therapeutics. The remaining authors have no conflicts of interest to declare. Accepted for publication November 2018. © 2018 American College of Sports Medicine

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