Pre-Altitude Serum Ferritin Levels and Daily Oral Iron Supplement Dose Mediate Iron Parameter and Hemoglobin Mass Responses to Altitude Exposure

Abstract

PurposeTo 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.MethodsHematological 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)].ResultsAltitude 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]).ConclusionOral 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.

Live high, train low – influence on resting and post‐exercise hepcidin levels

“…Plasma ferritin decreased in non‐iron‐supplemented athletes after 11 and 14 days of hypoxic exposure. These findings are consistent with the decrease in serum ferritin levels we reported in non‐oral‐iron‐supplemented athletes exposed to low to moderate altitudes (1350–3000 m) between 2004 and 2014 (Govus et al., ). In comparison, oral iron‐supplemented athletes mostly maintained their plasma ferritin levels during the intervention period, further suggesting athletes with low pre‐altitude iron stores are likely to maintain iron balance during hypoxic exposure when supplemented with a sufficient daily dose of iron.…”

Altitude exposure as a training & iron overload management strategy post leukemia

“…The decrease in serum ferritin with altitude exposure is supported by values previously reported in iron replete athletes (serum ferritin >100 g L −1 ). 18 Similarly, the increase in Hb mass is in line with the expected increase of 3.5% associated with the altitude dose of 823 km h completed by the player. 15 Given each additional gram of hemoglobin is suggested to increase VO 2max by ∼4.9 mL min −1 , 25 we can estimate that the player in the current case study likely experienced a 180 mL min −1 or 3% increase in VO 2max .…”

“…length and degree of altitude exposure) and iron stores. 18 Athletes with higher serum ferritin levels prior to commencing altitude exposure achieve greater increases in Hb mass compared to their iron deficient counterparts. 19 Accordingly, in athletes with excessive iron levels altitude training may present an effective way of managing serum ferritin by means of mobilising iron into red blood cells, thus simultaneously improving O 2 carrying capacity.…”

Influence of combined iron supplementation and simulated hypoxia on the haematological module of the athlete biological passport

“…Since iron is an essential component of haemoglobin, iron demands are increased during altitude exposure . Therefore, athletes engaging in altitude training are usually advised to take supplementary iron during the period of altitude exposure even if their iron stores are deemed normal . Further, it is not uncommon for supplementation to begin a number of weeks prior to going to altitude, as was the case in the present study, to ensure adequate iron is available for erythropoiesis.…”