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

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.

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).

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.

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.