EPO, TESTING, AND PERFORMANCE
Rushall, B. S. (2008). Rushall Comment August 1, 2008.
The situations and assertions about EPO (erythropoietin) and sporting performance seem to involve a confused lack of understanding of human functioning. One form of incorrect thinking claims that if the oxygen carrying capacity of the blood is increased, the extra oxygen will be used in performance and so endurance activities (e.g., volume of training or endurance competitions) will benefit. That is very likely a false assumption. The few research papers that actually have looked at the relationship between performance and EPO or increased oxygen carrying capacity in the blood show that it is not the blood-borne supply of oxygen that is important for performance but the oxygen extracting capacity of the cells (mainly the number of mitochondria) in the muscles that actually govern performance. That leads to the assertion that even if the circulatory system delivered 100% oxygen to the cells, performance would not improve but would be limited to maximal extraction capacity (VO2 ) at the cellular level. Traditionally, circulation has been referred to as central capacity and the muscle level as peripheral capacity.
There is no doubt that EPO and its recombinant analogs do help the physical functioning of people who have less oxygen delivered to the cells than the maximum extraction capacity of those cells (Spivak, 2001). That is why it is valuable for some cancer conditions (e.g., Lance Armstrong in his recovery regime) and anemia, among other problems. The extra EPO contributes to the elevation of the quantity of oxygen that is delivered to the working muscle cells and performance improves to a "normal" level from an abnormally low level. However, to further increase the oxygen carrying capacity of the blood to excessive levels results in only delivering excessive levels of oxygen to the cells that are working at 100% of their capacity (i.e., when they are fully trained in aerobic function). There is no further "capacity enhancement" because performance is not related to excessive levels of red cells, hemoglobin counts, or levels of EPO. Aerobic performance is limited by what happens at the cellular level when the circulatory system works optimally and supplies the maximum-needed volume of oxygen. The point is that individuals can extract a finite maximum amount of oxygen from the blood (VO2max) and no more. An excessive supply of oxygen will lead to the excess continuing on in the circulation blood.
A number of research articles have variously shown that EPO (e.g., Friedman et al, 2005) and red blood cell count (Nelson, Doan, Ryan, Byrnes, & Brothers, 2009). are unrelated and that sea-level performance is not associated with total hemoglobin mass. While the theory relating factors associated with oxygen capacity with performance enhancement might seem rational because it is with fitness-changing individuals, when evidence is produced for trained athletes, that theory is not supported. This is but one instance of a physiological paradox (Zhou, Ernst, & Wang, 2002). EPO is of benefit to those in need (the diseased or untrained) but not to those who are highly trained. The misinformation associated with EPO "benefits" obtained from exogenous introduction or altitude adaptation has emerged despite the long-known fact that excessive oxygen breathing does not improve performance; it only reduces the requirement to breathe frequently. A similar lack of association occurs with hemoglobin mass (Nelson, Doan, Ryan, Byrnes, & Brothers, 2009). If excessive inspired oxygen, which would result in maximum oxygenation of the blood, does not improve performance why would maximum or excessive oxygenation of the blood through EPO stimulation or altitude adaptation have an effect? That answer is; it would not.
It is alarming that so many elite, highly trained athletes use EPO in the belief that it is performance enhancing. That myth is supported by the Drugs-in-sport movement that tests for it under the description of it being "performance enhancing". For super-talented and fully fit individuals it is about as useful as is human growth hormone, another substance that is banned but unrelated to or not associated with performance enhancement.
A positive drug test for exogenous EPO does not necessarily show a "cheating-benefit". It more likely shows the uninformed belief that the substance is performance enhancing, and that the individual is used by those who market/supply EPO and the drugs-in-sport movement that tests for it based on one or more false premises.
It is possible that EPO augmentation might be associated with performance improvements because of an associated placebo effect. When that is the case, it is the belief of effect that promotes improvement, not the substance. There are plenty of avenues for increasing beliefs that are more acceptable than injecting or consuming a substance such as EPO if placebo effects are desired.
Billat, L. V. (1996). Use of blood lactate measurements for prediction of exercise performance and for control of training: Recommendations for long-distance running. Sports Medicine, 22, 157-175. [http://coachsci.sdsu.edu/csa/vol46/billat.htm]
Friedmann, B., Frese, F., Menold, E., Kauper, F., Jost, J., & Bartsch, P. (2005). Individual variation in the erythropoietic response to altitude training in elite junior swimmers. British Journal of Sports Medicine, 39(3), 148-153. [http://coachsci.sdsu.edu/csa/vol146/friedman.htm]
Nelson, J. L., Doan, B. K., Ryan, B., Byrnes, W. C., & Brothers, M. D. (2009). Relationship between total hemoglobin mass and aerobic performance of sea level residents exposed to 2210m. ACSM 56th Annual Meeting, Seattle, Washington. Presentation number 2362. [http://coachsci.sdsu.edu/csa/vol174/nelson.htm]
Noakes, T. D. (1997). Challenging beliefs: ex Africa semper aliquid novi. Medicine and Science in Sports and Exercise, 29, 571-590. [http://coachsci.sdsu.edu/csa/vol46/noakes.htm] (very important).
Noakes, T. D. (2000). Physiological models to understand exercise fatigue and the adaptations that predict or enhance athletic performance. Scandinavian Journal of Medicine and Science in Sports, 10, 123-145. [http://coachsci.sdsu.edu/csa/vol71/noakes.htm](very important).
Spivak, J. L. (2001). Erythropoietin use and abuse: When physiology and pharmacology collide. Advances in Experimental Medicine and Biology, 502, 207-224. [http://coachsci.sdsu.edu/csa/vol116/spivak.htm]
Zhou, B., Ernst, M., & Wang, Y. T. (2002). Limiting factors for maximal oxygen consumption within male college students versus collegiate distance runners. Medicine and Science in Sports and Exercise, 34(5), [http://coachsci.sdsu.edu/csa/vol101/zhou2.htm]
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