Haemoglobin Mass and Running Time Trial Performance after Recombinant Human Erythropoietin Administration in Trained Men Je ´ro ˆ me Durussel 1 , Evangelia Daskalaki 2 , Martin Anderson 1 , Tushar Chatterji 1 , Diresibachew H. Wondimu 1,3 , Neal Padmanabhan 1 , Rajan K. Patel 1 , John D. McClure 1 , Yannis P. Pitsiladis 1 * 1 Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom, 2 Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, United Kingdom, 3 Department of Medical Physiology, Addis Ababa University, Addis Ababa, Ethiopia Abstract Recombinant human erythropoietin (rHuEpo) increases haemoglobin mass (Hb mass ) and maximal oxygen uptake (v ˙O 2 max ). Purpose: This study defined the time course of changes in Hb mass ,v ˙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 IUNkg 21 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. v ˙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 (10:3061:07 min:sec vs. 11:0861:15 min:sec, p,0.001) and remained significantly enhanced by ,3% 4 weeks after administration (10:46 61:13 min:sec, p ,0.001), while v ˙ O 2 max was also significantly increased post administration (60.765.8 mLNmin 21 Nkg 21 vs. 56.066.2 mLNmin 21 Nkg 21 ,p,0.001) and remained significantly increased 4 weeks after rHuEpo (58.065.6 mLNmin 21 Nkg 21 , p = 0.021). Hb mass was significantly increased at the end of administration compared to baseline (15.261.5 gNkg 21 vs. 12.761.2 gNkg 21 ,p,0.001). The rate of decrease in Hb mass toward baseline values post rHuEpo was similar to that of the increase during administration (20.53 gNkg 21 Nwk 21 , 95% confidence interval (CI) (20.68, 20.38) vs. 0.54 gNkg 21N wk 21 , CI (0.46, 0.63)) but Hb mass was still significantly elevated 4 weeks after administration compared to baseline (13.761.1 gNkg 21 ,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 v ˙O 2 max and Hb mass . Citation: Durussel J, Daskalaki E, Anderson M, Chatterji T, Wondimu DH, et al. (2013) Haemoglobin Mass and Running Time Trial Performance after Recombinant Human Erythropoietin Administration in Trained Men. PLoS ONE 8(2): e56151. doi:10.1371/journal.pone.0056151 Editor: Elias T. Zambidis, Johns Hopkins School of Medicine, United States of America Received October 23, 2012; Accepted January 5, 2013; Published February 13, 2013 Copyright: ß 2013 Durussel et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Funding: This study was part of a larger research project supported and funded by World Anti-Doping Agency (08C19YP). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Competing Interests: The authors have declared that no competing interests exist. * E-mail: Yannis.Pitsiladis@glasgow.ac.uk Introduction Erythropoietin is a glycoprotein hormone produced primarily in the kidney that regulates red blood cell mass by stimulating the survival, proliferation and differentiation of erythrocytic progen- itors [1]. In healthy subjects, administration of recombinant human erythropoietin (rHuEpo) increases haemoglobin concen- tration not only by the well known increase in red blood cell mass but also by a decrease in plasma volume [2,3,4]. The decrease in plasma volume, which precedes the increase in red cell mass, appears to be a rapid responding mechanism regulated by the renin-angiotensin-aldosterone system to control haematocrit [2,3]. Theoretically, normal human red blood cells can persist in the circulation for approximately 17 weeks [5]. However, neocytolysis, the selective hemolysis of young circulating red blood cells which contributes to the regulation of red cell mass, seems to appear during specific conditions that cause a rapid decrease in erythropoietin levels such as spaceflight, high altitude exposure or blood doping [5,6,7,8,9]. Little is known about the time course of these mechanisms post rHuEpo administrations. In this study, heamoglobin mass (Hb mass ) and related blood volumes were repeatedly determined using the optimized carbon monoxide (CO) PLOS ONE | www.plosone.org 1 February 2013 | Volume 8 | Issue 2 | e56151