EPO – The Endurance Athlete’s Steroid

Read the sports section of any newspaper lately and you will no doubt see the headlines dealing with Lance Armstrong’s alleged use of EPO. Apparently, he is accused of testing positive for having used the substance to enhance his performance during several Tour de France cycle races. Actually, the use of EPO in endurance exercise is nothing new and it has been recognized as an ergogenic or performance enhancing substance for several years. This article aims to provide some basic information on EPO, its mechanism of operation and the dangers involved with its use by athletes.

What is EPO?

EPO is an abbreviation for Best Legal Steroids alternatives for sale erthropoetin. Contrary to many of the articles currently in the media, erythropoietin is not a drug – it is a peptide hormone produced naturally in the body, manufactured and released from the kidney. The role of EPO is to stimulate bone marrow to manufacture more erythrocytes (red blood cells). This has the effect of increasing the hematocrit – the percentage of blood by volume composed of erythrocytes. Special oxygen sensitive cells in the kidney are able to determine the concentration of oxygen in the blood, and this is the suspected mechanism for its release into the blood stream.

A good example of EPO’s working is the effect of increased altitude on blood oxygen concentration. As altitude progressively increases, atmospheric pressure decreases. Therefore the amount of air at altitude decreases, decreasing the available oxygen (nitrogen, carbon dioxide too) needed for respiration. The kidney cells detect this decrease in oxygen and release EPO into the bloodstream to stimulate the production of more erythrocytes. Erythrocytes contain a protein called hemoglobin, which via the blood circulatory system transports oxygen from the lungs to other parts of the body and to a lesser degree carries carbon dioxide back to the lungs where it is exhaled.