Year-to-year variability in haemoglobin mass response to two altitude training camps

Abstract

Aim: To quantify the year-to-year variability of altitude-induced changes in haemoglobin mass (Hb(mass)) in elite team-sport athletes.

Methods: 12 Australian-Footballers completed a 19-day (ALT1) and 18-day (ALT2) moderate altitude (∼2100 m), training camp separated by 12 months. An additional 20 participants completed only one of the two training camps (ALT1 additional n=9, ALT2 additional n=11). Total Hb(mass) was assessed using carbon monoxide rebreathing before (PRE), after (POST₁) and 4 weeks after each camp. The typical error of Hb(mass) for the pooled data of all 32 participants was 2.6%. A contemporary statistics analysis was used with the smallest worthwhile change set to 2% for Hb(mass).

Results: POST₁ Hb(mass) was very likely increased in ALT1 (3.6 ± 1.6%, n=19; mean ± ∼90 CL) as well as ALT2 (4.4 ± 1.3%, n=23) with an individual responsiveness of 1.3% and 2.2%, respectively. There was a small correlation between ALT1 and ALT2 (R=0.21, p=0.59) for a change in Hb(mass), but a moderately inverse relationship between the change in Hb(mass) and initial relative Hb(mass) (g/kg (R=-0.51, p=0.04)).

Conclusions: Two preseason moderate altitude camps 1 year apart yielded a similar (4%) mean increase in Hb(mass) of elite footballers, with an individual responsiveness of approximately half the group mean effect, indicating that most players gained benefit. Nevertheless, the same individuals generally did not change their Hb(mass) consistently from year to year. Thus, a 'responder' or 'non-responder' to altitude for Hb(mass) does not appear to be a fixed trait.

Keywords: Altitude; Elite performance; Exercise; Physiology.

Figure 1

Timeline of haemoglobin mass (Hb_mass) collection over ALT1 and ALT2.

Figure 2

Percentage changes in haemoglobin mass (Hb_mass) (mean±90% CI) after altitude ALT1 and ALT2.

Figure 3

Change in haemoglobin mass (Hb_mass) versus initial RelHb_mass in healthy and BodyMass_stable participants pooled for ALT1 and ALT2 altitude camps.

Figure 4

Change in haemoglobin mass (Hb_mass) during ALT1 versus change in Hb_mass during ALT2. Three participants were removed from this analysis due to illness throughout the study period (n=9). Grey filled circle represents an outlier; regression line and associated equations when the outlier is removed are shown in grey.

Figure 5

Change in haemoglobin mass (Hb_mass) in ill and healthy participants (A), as well as change in mass (B) and change in Hb_mass (C) in BodyMass_stable and BodyMass_loss groups.

Figure 6

Reticulocyte (A) and erythropoietin (EPO) (B) response during ALT2. Black circles and error bars show group change as mean±SD and grey circles show individual responses. Dark grey broken lines depict responses of three participants who reported illness before (b+c) and during (a) altitude exposure. NB. EPO data at PRE missing for participant (b) due to being absent from testing as a result of illness.