Govus et al. 2015, Pre-altitude ferritin, iron dose and haemoglobin-mass response

PLoS One 10(8):e0135120. Retrospective analysis of 178 athletes at altitude. Iron supplementation showed a clear dose-response on the haemoglobin-mass gain: no supplement ~1.1%, 105 mg/day ~3.3%, 210 mg/day ~4.0%. Companion work (Garvican-Lewis et al. 2016) found iron-deficient athletes on an adequate dose gained the most (~7%). Iron availability gates the erythropoietic response, so screen ferritin and supplement rather than exclude. Moderate-strong for the iron requirement.