Iron matters before anemia

A controlled trial in previously untrained, non‑anemic women reported that marginal iron deficiency blunted increases in maximal oxygen uptake after four weeks of cycle ergometer training. (ajcn.nutrition.org) A randomized study of 42 iron‑depleted, non‑anemic women (serum ferritin <16 µg/L) given 100 mg ferrous sulfate daily during six weeks of supervised training recorded larger improvements in 15‑km cycle time in the supplemented group versus placebo.. (journals.physiology.org) A 2014 double‑blind trial that randomized 14 distance runners (baseline ferritin 30–100 µg/L) to three IV ferric‑carboxymaltose injections (100 mg each) found reduced perceived fatigue and mood disturbance at six weeks but no consistent gains in hemoglobin mass or race performance.. (journals.plos.org) A large review of student‑athletes (17,519 participants across 62 sports) reported 53.9% were hypoferritinemic using a <50 µg/L cutoff and 23.0% met absolute iron‑deficiency criteria (<20 µg/L).. (mayoclinic.elsevierpure.com) Recent guideline analyses and conference abstracts have pushed for harmonized ferritin cutoffs, proposing a unified diagnostic threshold of ferritin <30 ng/mL for iron deficiency, while sports medicine groups frequently recommend athlete‑specific targets of ~40–50 ng/mL to catch early deficits.. (ashpublications.org) Physiological work shows intense exercise raises the iron‑regulatory hormone hepcidin for several hours after training, which suppresses dietary iron absorption and helps explain why timing of oral supplementation relative to sessions affects how quickly stores recover.. (germanjournalsportsmedicine.com) Small studies of wrestlers and other grappling athletes have documented statistically lower ferritin and microelement values in cohorts with heavy training loads (two sessions per day plus strength work), and combat disciplines commonly require multiple matches in a single competition day—both factors linked to higher risk of depleted iron stores.. (stk-sport.co.uk)