Pre-Altitude Serum Ferritin Levels and Daily Oral Iron Supplement Dose Mediate Iron Parameter and Hemoglobin Mass Responses to Altitude Exposure.
OBJECTIVE
To investigate the influence of daily oral iron supplementation on changes in hemoglobin mass (Hbmass) and iron parameters after 2-4 weeks of moderate altitude exposure.


METHODS
Hematological data collected from 178 athletes (98 males, 80 females) exposed to moderate altitude (1,350-3,000 m) were analysed using linear regression to determine how altitude exposure combined with oral iron supplementation influenced Hbmass, total iron incorporation (TII) and blood iron parameters [ferritin and transferrin saturation (TSAT)].


RESULTS
Altitude exposure (mean ± s: 21 ± 3 days) increased Hbmass by 1.1% [-0.4, 2.6], 3.3% [1.7, 4.8], and 4.0% [2.0, 6.1] from pre-altitude levels in athletes who ingested nil, 105 mg and 210 mg respectively, of oral iron supplement daily. Serum ferritin levels decreased by -33.2% [-46.9, -15.9] and 13.8% [-32.2, 9.7] from pre-altitude levels in athletes who supplemented with nil and 105 mg of oral iron supplement daily, but increased by 36.8% [1.3, 84.8] in athletes supplemented with 210 mg of oral iron daily. Finally, athletes who ingested either 105 mg or 210 mg of oral iron supplement daily had a greater TII compared with non-supplemented athletes (0 versus 105 mg: effect size (d) = -1.88 [-2.56, -1.17]; 0 versus 210 mg: effect size (d) = -2.87 [-3.88, -1.66]).


CONCLUSIONS
Oral iron supplementation during 2-4 weeks of moderate altitude exposure may enhance Hbmass production and assist the maintenance of iron balance in some athletes with low pre-altitude iron stores.
Centre for Exercise and Sports Science Research, School of Exercise and Health Science, Edith Cowan University, Joondalup, WA, Australia.
Andrew D
AD
Govus
Department of Physiology, Australian Institute of Sport, Bruce, ACT, Australia; Research Institute for Sport and Exercise, University of Canberra, Bruce, ACT, Australia.
Laura A
LA
Garvican-Lewis
Centre for Exercise and Sports Science Research, School of Exercise and Health Science, Edith Cowan University, Joondalup, WA, Australia.
Chris R
CR
Abbiss
School of Sport Science, Exercise & Health, University of Western Australia, Crawley, WA, Australia.
Peter
P
Peeling
Department of Physiology, Australian Institute of Sport, Bruce, ACT, Australia; Exercise Physiology Laboratory, Flinders University, Bedford Park, SA, Australia; Research Institute for Sport and Exercise, University of Canberra, Bruce, ACT, Australia.
Christopher J
CJ
Gore
D000531:Altitude; D056352:Athletes; D019587:Dietary Supplements; D005260:Female; D005293:Ferritins / Q000097:blood*; D006454:Hemoglobins / Q000378:metabolism*; D006801:Humans; D007501:Iron / Q000008:administration & dosage* / Q000378:metabolism*; D008297:Male; D013997:Time Factors
D006454:Hemoglobins; D005293:Ferritins; D007501:Iron