mance?Erythropoietin (EPO) is a glycoprotein hormone secreted naturally, by the cells of the peritubular capillary endothelium of the kidneys but also to a very small extent in the liver. It is usually secreted in response to hypoxia in the renal arterial circulation. Its release stimulates bone marrow to increase its production of red blood cells (erythropoiesis), and facilitate an increase in the oxygen carrying capacity of blood. Red blood cells are limited in their ability to unload all their oxygen at a muscle site. By increasing the number of red blood cells you increase the amount of oxygen being delivered to muscles. Increased oxygen delivery to working muscles improves aerobic performance. Indirectly, increasing oxygen delivery allows for increased use of fat for energy at greater workloads. Blood carries 20ml of oxygen per 100ml of blood in the arteries. At rest the body releases 4–5ml of oxygen per 100ml of blood. The rest remains bound to the hemoglobin. During intensive aerobic exercise about 15ml of oxygen per 100ml of blood can be released to the active muscles. The normal hematocrit (proportion of RBC) is between 40-54% in males and 37-47% in females. So a person with a hematocrit of 50% will have 50ml of red blood cells for every 100ml of blood. 100ml of blood contains 15 grams of hemoglobin. 1 gram of hemoglobin can carry 1.34ml of oxygen. Using rhEPO could raise hematocrit levels to say 55% in turn increasing the bloods hemoglobin content to 17.7 grams per 100ml. An increase of 3.6ml of oxygen per 100ml of blood. This result (20% increase) would translate into a serious advantage. Increasing RBC count will also increase blood volume somewhat. A greater blood volume means a larger cardiac output without increasing heart rate. Red blood cells are also important in the buffering of acid in the muscles. Larger amounts of RBC enable more lactic acid to be buffered.The foremost threat of rhEPO use is boosting hem...
