Haemoglobin mass and running time trial performance after recombinant human erythropoietin administration in trained men

<p>Recombinant human erythropoietin (rHuEpo) increases haemoglobin mass (Hbmass) and maximal oxygen uptake (v˙ O2 max).</p> <p>Purpose: This study defined the time course of changes in Hbmass, v˙ O2 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.</p> <p>Methods: 19 trained men received rHuEpo injections of 50 IUNkg21 body mass every two days for 4 weeks. Hbmass was determined weekly using the optimized carbon monoxide rebreathing method until 4 weeks after administration. v˙ O2 max and 3,000 m time trial performance were measured pre, post administration and at the end of the study.</p> <p>Results: Relative to baseline, running performance significantly improved by ,6% after administration (10:3061:07 min:sec vs. 11:0861:15 min:sec, p,0.001) and remained significantly enhanced by ,3% 4 weeks after administration (10:4661:13 min:sec, p,0.001), while v˙ O2 max was also significantly increased post administration (60.765.8 mLNmin21Nkg21 vs. 56.066.2 mLNmin21Nkg21, p,0.001) and remained significantly increased 4 weeks after rHuEpo (58.065.6 mLNmin21Nkg21, p = 0.021). Hbmass was significantly increased at the end of administration compared to baseline (15.261.5 gNkg21 vs. 12.761.2 gNkg21, p,0.001). The rate of decrease in Hbmass toward baseline values post rHuEpo was similar to that of the increase during administration (20.53 gNkg21Nwk21, 95% confidence interval (CI) (20.68, 20.38) vs. 0.54 gNkg21Nwk21, CI (0.46, 0.63)) but Hbmass was still significantly elevated 4 weeks after administration compared to baseline (13.761.1 gNkg21, p<0.001).</p> <p>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 v˙ O2 max and Hbmass.</p&gt

Resting blood pressure and heart rate before, during and 4 weeks post rHuEpo administration.

<p><i>N</i> = 19. Values are means (SD). No significant differences compared to baseline values were observed.</p

Individual changes in carboxyhaemoglobin.

<p>Each line corresponds to one subject. Individual mean value was calculated when more than one blood sample was collected per week. The bar graphs represent the mean values of the 19 subjects. The grey bars represent the 4 weeks of rHuEpo administration.</p

Haematocrit, haemoglobin concentration, reticulocytes, haemoglobin mass, blood volumes, carboxyhaemoglobin and body mass before, during and 4 weeks post rHuEpo administration.

<p><i>N</i> = 19. Values are means (SD). Significant differences compared to baseline values are indicated by *<i>P</i><0.05. Hb_mass: Haemoglobin mass.</p

Individual changes in Hb_mass (A), red cell (B), plasma (C) and blood (D) volume.

<p>Each line corresponds to one subject and each symbol corresponds to the same subject in all figures. Individual mean value was calculated when more than one blood sample was collected per week. The bar graphs represent the mean values of the 19 subjects. The grey bars represent the 4 weeks of rHuEpo administration.</p

Running 3,000 m time trial performance and maximal oxygen uptake.

<p>Group 1 included subjects who had a history of running (n = 9) and group 2 included the other subjects who were involved in other activities (n = 9). Values are means (SD). Significant differences compared to baseline values are indicated by *<i>P</i><0.05. Significant differences compared to the first 1,000 m split time within the same time trial. ^†<i>P</i><0.05. RPE: Borg’s rating of perceived exertion; O_{2 max}: Maximal oxygen uptake.</p

Changes in haemoglobin mass, blood, red cell and plasma volume during and for 4 weeks post rHuEpo administration.

<p><i>N</i> = 19. Values are means (95% confidence interval). Significant changes are indicated by *<i>P</i><0.05.</p