The Performance Effects of Microdose Recombinant Human Erythropoietin Administration and Carbon Monoxide Rebreathing.

Frequent, low doses of recombinant human erythropoietin (rHuEpo) have been shown to increase the oxygen carrying capacity of an athlete and enhance endurance performance, although its effect on repeated sprint ability (RSA) remains unknown. If the mechanisms behind improved RSA performance reside within the augmented O2 carrying capacity, then carbon monoxide (CO) inhalation should inhibit RSA. Purpose: The aim of this study was to assess the effects on maximal oxygen uptake (V˙O2max) and RSA of two interventions known to differentially influence blood oxygen carrying capacity. Methods: Fourteen endurance-trained individuals were administered microdoses of rHuEpo (20-40 IUkg) or placebo twice per week for 7 wk using a randomized, crossover design. V˙O2max and RSA were measured at baseline and after rHuEpo administration. Total hemoglobin mass (tHb-mass) was measured twice at baseline (14 and 7 d before the first injection), three times during rHuEpo administration (10, 24, and 38 d after the first rHuEpo injection) and twice after the cessation of rHuEpo administration (7 and 21 d after the final injection) using the optimized CO rebreathing method. V˙O2max and RSA also were assessed in a separate cohort of 11.