Haemoglobin Mass and Running Time Trial Performance after Recombinant Human Erythropoietin Administration in Trained Men.

Recombinant human erythropoietin (rHuEpo) increases haemoglobin mass (Hb_mass) and maximal oxygen uptake ( O_{2 max}). Purpose: This study defined the time course of changes in Hb_mass, O_{2 max} as well as running time trial performance following 4 weeks of rHuEpo administration to determine whether the laboratory observations would translate into actual improvements in running performance in the field. Methods: 19 trained men received rHuEpo injections of 50 IU•kg⁻¹ body mass every two days for 4 weeks. Hb_mass was determined weekly using the optimized carbon monoxide rebreathing method until 4 weeks after administration. O_{2 max} and 3,000 m time trial performance were measured pre, post administration and at the end of the study. Results: Relative to baseline, running performance significantly improved by ∼6% after administration (10∶30±1∶07 min:sec vs. 11∶08±1∶15 min:sec, p<0.001) and remained significantly enhanced by ∼3% 4 weeks after administration (10∶46±1∶13 min:sec, p<0.001), while O_{2 max} was also significantly increased post administration (60.7±5.8 mL•min⁻¹•kg⁻¹ vs. 56.0±6.2 mL•min⁻¹•kg⁻¹, p<0.001) and remained significantly increased 4 weeks after rHuEpo (58.0±5.6 mL•min⁻¹•kg⁻¹, p = 0.021). Hb_mass was significantly increased at the end of administration compared to baseline (15.2±1.5 g•kg⁻¹ vs. 12.7±1.2 g•kg⁻¹, p<0.001). The rate of decrease in Hb_mass toward baseline values post rHuEpo was similar to that of the increase during administration (−0.53 g•kg⁻¹•wk⁻¹, 95% confidence interval (CI) (−0.68, −0.38) vs. 0.54 g•kg^−1•wk⁻¹, CI (0.46, 0.63)) but Hb_mass was still significantly elevated 4 weeks after administration compared to baseline (13.7±1.1 g•kg⁻¹, p<0.001). Conclusion: Running performance was improved following 4 weeks of rHuEpo and remained elevated 4 weeks after administration compared to baseline. These field performance effects coincided with rHuEpo-induced elevated O_{2 max} and Hb_mass. [ABSTRACT FROM AUTHOR]