Why iron matters for performance

• Oxygen delivery: Hemoglobin uses iron to transport oxygen to working muscles.
• Energy production: Iron-dependent enzymes drive mitochondrial ATP production.
• Neuromuscular function: Low iron raises perceived exertion, heart rate at given pace, and impairs training adaptations.
• Immunity and cognition: Deficiency can increase illness risk and reduce focus and reaction time.

Ferritin, explained

Ferritin is your iron storage protein. It’s the earliest and most sensitive lab marker of iron depletion. You can have normal hemoglobin but low ferritin—this stage already affects performance.

Why female athletes are at higher risk

• Menstrual blood loss, especially with heavy periods or copper IUDs.
• Higher training loads: footstrike hemolysis, gut microbleeds, and inflammation-driven iron regulation.
• Dietary patterns: lower intake of heme iron, vegetarian/vegan diets, or low energy availability.
• Altitude exposure: increased red blood cell production demands more iron.

Performance red flags

• Unusual fatigue, “heavy legs,” higher heart rate or RPE at easy paces.
• Plateau or decline despite consistent training and sleep.
• Shortness of breath, dizziness, headaches, cold hands/feet.
• Pale skin, brittle nails, hair shedding, restless legs, frequent illness.

Testing: what to order and how to read it

Ask your clinician for:

• Ferritin (iron stores)
• CBC: hemoglobin, hematocrit, MCV, RDW
• Iron panel: serum iron, transferrin or TIBC, transferrin saturation (TSAT)
• CRP (or hs-CRP) to check for inflammation that can falsely elevate ferritin

Typical interpretation in athletes

• Ferritin

  • Under ~15 µg/L: iron deficiency is very likely.
  • 15–30 µg/L: depleted stores; performance often suffers.
  • 30–50 µg/L: many endurance athletes feel better above this range; target is often 40–70 µg/L.
  • Altitude blocks may warrant higher stores ( discuss with your sports clinician ).

• TSAT

  • Under ~20% suggests iron-deficient erythropoiesis (iron not reaching RBC production effectively).

• Hemoglobin

  • Normal with low ferritin: “non-anemic iron deficiency”—already impactful.
  • Low hemoglobin: iron-deficiency anemia.

• CRP

  • High CRP can make ferritin look normal or high; rely more on TSAT and the full picture.

Fixing the problem: food-first, then targeted supplements

1) Nutrition strategies

• Include heme iron sources 3–5 times/week: lean red meat, dark poultry, sardines, mussels, clams.
• Plant options: lentils, beans, tofu/tempeh, edamame, pumpkin seeds, cashews, quinoa, fortified cereals.
• Boost absorption with vitamin C foods: citrus, berries, kiwi, peppers, tomatoes.
• Timing matters: keep iron-rich meals away (by ~1–2 hours) from coffee/tea, high-calcium foods/supplements, and large doses of zinc.
• Preparation tips: soak/sprout legumes and grains; use cast-iron cookware for acidic dishes (tomato sauce, chili).

2) Supplementation (with medical guidance)

• Common forms: ferrous sulfate, gluconate, or fumarate; newer options like polysaccharide iron may be gentler.
• Absorption improves when:

  • Taken on an empty stomach or with vitamin C (if tolerated).
  • Dosed in the morning and not within 3–6 hours after hard training (hepcidin rises post-exercise).
  • Given on alternate days for some athletes, which can reduce side effects and improve absorption.

• Side effects: nausea, constipation, dark stools. Lower the dose, switch formulation, take with a small snack, or consider alternate-day dosing if needed.

3) Training considerations while repleting iron

• Prioritize aerobic base and technique; limit extended high-intensity bouts until energy and HR responses normalize.
• Plan iron dosing away from hard sessions; favor morning dosing on easier days.
• If preparing for altitude, aim to optimize ferritin beforehand.

How long until you feel better?

• 1–2 weeks: energy and “pop” can start improving as the bone marrow responds.
• 2–4 weeks: hemoglobin rises if it was low.
• 6–12+ weeks: ferritin stores rebuild; many athletes continue supplementation 2–3 months after labs normalize to fully replenish stores (per clinician advice).

Monitoring plan

• Baseline: CBC, ferritin, iron panel, CRP.
• Recheck in ~6–8 weeks after nutrition/supplement changes.
• If inadequate response: assess adherence/timing, GI tolerance, inflammation, menstrual losses, altitude/training load, and screen for malabsorption or occult blood loss as guided by your clinician.
• Maintenance: 1–2 checks per year, plus before heavy training blocks or altitude camps.

Special situations for female athletes

• Heavy menstrual bleeding: discuss options that reduce blood loss (e.g., certain hormonal IUDs or OCPs) with your clinician.
• Plant-based diets: pay closer attention to total iron intake, vitamin C pairing, and inhibitors; consider fortified foods or supplements if labs trend low.
• Low energy availability/RED-S: address fueling first; iron won’t fix under-fueling.
• GI symptoms on iron: try alternate-day dosing, different formulations, or liquid forms; rule out other conditions if persistent.

Quick-start checklist

• Notice a persistent dip in training? Get labs: ferritin, CBC, iron panel, CRP.
• If ferritin <30–35 µg/L or TSAT <20%, work with a clinician on a plan.
• Improve iron-rich meals and absorption timing immediately.
• Consider clinician-guided supplementation; recheck in 6–8 weeks.
• Adjust training stress until symptoms and metrics improve.