How does EPO increase the haematocrit in elite Tour De France riders? May 29, 2007Posted by Jacob Sondergaard in Uncategorized.
EPO abuse by elite cyclist is much up in the media at the moment. My master thesis in exercise physiology is about EPO, which non-hemoglobine mediated effects on VO2-max you get from prolonged EPO use. Additionaly I will investigate if EPO has any anti-inflammatory effects on day to day performance.
EPO is mainly produced in the human liver due to low CaO2 (low arterial O2 content) By administering EPO the CaO2 will increase by increasing the production of red blood cells in the bone marrow. This will increase the haematocrit and thereby the bloods ability to carry oxygen to the oxygen consuming tissues. This will increase the VO2-max which is a predictor of succes in i.e. Tour De France.
EPO has another function whereby it increases the haematocrit besides from increased amount of red blood cells and that is by instantly decreasing the plasmavolume. This happens by an inhibition of the renin-angiotensin-aldosteron axis. By decreasing the plasma volume the CaO2 will increase and the blood volume (red blood cells + plasma volume) will decrease instantly. After 7-10 days the red blood cell mass will increase and thereby normalize the blood volume again.
In summary, EPO increases haematocrit by instantaniously decreasing plasma volume, and after a week by increasing red blood cell mass.
More update from this science perspective will be available on this site in the near future.