Additive Effect of EPO and Altitude on Hemoglobin Mass But Not Peak Oxygen Uptake.

Purpose: This study evaluated whether recombinant human erythropoietin (rhEpo) treatment combined with hypoxia provided an additive effect on hemoglobin mass (Hb mass ) and peak oxygen uptake (V̇O 2peak ) compared with altitude or rhEpo alone.

Methods: Thirty-nine participants underwent two interventions, each containing 4-wk baseline (PRE 1-4), 4-wk exposure at sea level or 2320 m of altitude (INT 1-4), and 4-wk follow-up (POST 1-4). Participants were randomly assigned to 20 IU·kg -1 rhEpo or placebo injections every second day for 3 wk during the exposure period at sea level (SL-EPO, n = 25; SL-PLA, n = 9) or at altitude (ALT-EPO, n = 12; ALT-PLA, n = 27).

Results: Hb mass displayed a significant time-treatment effect ( P < 0.001) when comparing ALT-EPO and ALT-PLA. Specifically, the increase in Hb mass was higher ( P < 0.05 to P < 0.001) for ALT-EPO from INT 2 to POST 3 except for POST 2. Similarly, a significant time-treatment effect ( P < 0.001) existed for changes in Hb mass when comparing ALT-EPO with SL-EPO, with the increase in Hb mass being higher ( P < 0.01 to P < 0.001) for ALT-EPO from INT 2 to POST 4. A significant time-treatment effect was present when SL-PLA was compared with ALT-PLA ( P < 0.05) and SL-EPO ( P < 0.05). For V̇O 2peak , the time-treatment interaction was not significant when comparing ALT-EPO to ALT-PLA. However, when ALT-EPO was compared with SL-EPO, a significant time-treatment interaction existed ( P < 0.001) due to a decrease in V̇O 2peak during altitude.

Conclusions: The combined treatment of microdoses of rhEpo and altitude exposure results in an additive increase in Hb mass but does not significantly enhance V̇O 2peak compared with each treatment alone.