Impact of baseline serum ferritin and supplemental iron on altitude-induced hemoglobin mass response in elite athletes

The present study explored the impact of pre-altitude serum (s)-ferritin and iron supplementation on changes in hemoglobin mass (ΔHbmass) following altitude training. Measures of Hbmass and s-ferritin from 107 altitude sojourns (9–28 days at 1800–2500 m) with world-class endurance athletes (males n = 41, females n = 25) were analyzed together with iron supplementation and self-reported illness. Altitude sojourns with a hypoxic dose [median (range)] of 1169 (912) km·h increased Hbmass (mean ± SD) 36 ± 38 g (3.7 ± 3.7%, p 100 µg·L−1, respectively, with no group difference (p = 0.400). Hbmass increased by 4.1 ± 3.9%, 3.0 ± 3.0% and 3.7 ± 4.7% without, ≤50 mg·day−1 or >50 mg·day−1 supplemental iron, respectively (p = 0.399). Linear mixed model analysis revealed no interaction between pre-altitude s-ferritin and iron supplementation on ΔHbmass (p = 0.906). However, each 100 km·h increase in hypoxic dose augmented ΔHbmass by an additional 0.4% (95% CI: 0.1–0.7%; p = 0.012), while each 1 g·kg−1 higher pre-altitude Hbmass reduced ΔHbmass by −1% (−1.6 to −0.5; p < 0.001), and illness lowered ΔHbmass by −5.7% (−8.3 to −3.1%; p < 0.001). In conclusion, pre-altitude s-ferritin or iron supplementation were not related to the altitude-induced increase in Hbmass (3.7%) in world-class endurance athletes with clinically normal iron stores

Sex difference (%) for performance in running and jumping disciplines from age 11 to 18.

<p>Data are mean and 95% CIs for 60 m (panel A), 800 m (panel B), long jump (panel C) and high jump (panel D) for top 100 Norwegian male and female performers in each discipline.</p

Performance development from age 11 to 18 in running and jumping disciplines.

<p>Data are mean ± SD for 60 m (panel A), 800 m (panel B) long jump (panel C) and high jump (panel D) for top 100 Norwegian male and female performers in each discipline.</p

Sex ratio in running and jumping performance for 11–18 yr old males and females.

<p>Data are calculated from mean results of top 100 Norwegian male and female performers in each discipline.</p><p>Sex ratio in running and jumping performance for 11–18 yr old males and females.</p