Your statement also hints at the idea that being able to train at higher workloads than you otherwise would be able, will provide a benefit even after the EPO-induced increase in O2 delivery fades.<<
Maximal oxygen consumption and time to exhaustion are enhanced for about three weeks post EPO treatment. I don’t know if I inferred anything else, if I did I’m sorry.
Iron is only a limiter when there is a deficiency. For a vast majority of people there is more than enough iron in the body to support the relatively small increase in RBC production EPO causes.<<
I disagree with the idea that there is more than enough iron in one’s system without supra-physiological amounts of iron when using EPO. Iron is a concern with EPO treatment. A study by Rutherford is one study that demonstrated the interplay between iron and erythropoietin (Rutherford, et al. 1994).
The addition of oral iron during the erythropoietin treatment was believed to provide an adequate source of iron for the production new red blood cells. The subjects received one of three dosing regimens of erythropoietin over 14 days and then were followed-up at day 24. In all cases, the baseline hemoglobin increased in these subjects by approximately 1g/dl. This increase reflected the enhanced erythropoiesis produced by erythropoietin supplementation.
The subjects were unable to maintain adequate serum iron levels despite the oral iron supplementation. Transferrin saturation at the onset of the study was approximately 40% (normal). After 13 days of erythropoietin treatment, the average transferrin saturation fell to about 10%. This drop showed that developing red cells removed iron from the circulating transferrin at a rate faster than it could be replaced, either from iron stores or from orally absorbed iron. With the cessation of erythropoietin treatment the plasma transferrin saturation returned to its baseline of about 40%. This was because the red cell precursors were no longer pushed into overdrive activity by surplus erythropoietin. Erythropoietin availability and iron use returned to their normal balance. As a result athletes usually take large amounts of iron.
Also using flow cytometric assessment of volume and volume concentration, it was found that the newly formed cells associated with EPO administration had increased erythrocyte zinc protoporphyrin, decreased volume concentration, and decreased red cell volume. This suggests that, in normal subjects, use of EPO can result in the production of red cells that are indistinguishable from those seen in patients with iron deficiency anemia. “The identification of this relative (or functional) iron deficiency is important for assessing r-HuEPO use.”
(Macdougall IC, et al. Br. Med. J. 304:6821, 1992)
EPO has also been shown to bring about an increase in the overall number of reticulocytes, peaking at 5 days after EPO administration, as well as a decrease in serum ferritin, with the lowest point at 4.0 days after EPO administration. (Major A, et al. Br. J. Haematol. 87:605, 1997)
Perhaps unfortunately, if taken with even minimal medical supervision, the health risks are very low. The only significant risk is the risk of getting caught.<<
I would disagree with that statement. There are significant risks in taking EPO under minimal medical supervision. I guess it depends on what you mean by minimal.