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How much does EPO improve performance in Racehorses?

A new study on human distance runners and their response to EPO has shown that four weeks of every-other-day injections improves 3000-meter running time by an average of 6%. A month after the end of the EPO injections, the runners were still 3% faster than they had been before receiving any EPO. In a world where just a 3% improvement is considered highly significant, a 6% improvement is very strong, and to have a 3% improvement even a month after injections were finished is noteworthy.

The study was funded by the World Anti-Doping Agency and “was designed primarily for other purposes.” This presumably refers to testing/detection of EPO in the runners’ blood over the entire period and perhaps beyond, that is, looking at changes in the body to see what is possible and what is not and what the rate of change in red blood cells normally is.

However, the current report made no mention of any such testing or test results.The study did note that EPO injections, which increase the body’s red blood cell mass (hence leading to greater oxygen delivery to muscles making them fatigue less), also decrease the body’s total blood plasma volume. This could account for health issues (heart attacks) suffered by some alleged EPO users in running and cycling over the past 20 years. It would also imply that EPO-using athletes need to boost their plasma volume if they participate in events where potential dehydration plays an important role (think about that with Lasix use).

I started this post about 10 days ago when this paper on EPO when it was first published, and it was not long thereafter that a story broke on the Paulick Report and Blood Horse with a "spike" in cardiac deaths in racing in California. While the CHRB denied the "spike" it is noteworthy that the rate of sudden deaths in California is high relative to the rest of the world and in the postmortem report on one horse it stated: "During this period there were 11 cases of sudden death due to cardiac failure. This represents an increase from four horses with this diagnosis during 2008-2009 and six with the same diagnosis in 2010-2011." I'll let you be the judge if that represents a "spike" or not.

It is generally a rather long bow to suggest that because of cardiac deaths in Thoroughbreds, we immediately suspect procrit/EPO (or ITPP or AICAR) as being used. The Thoroughbred, with its large spleen is effectively a natural blood doper (it dumps more than a third of its total blood volume with a splenic contraction) to start with so the efficacy of EPO or a similar substance is questionable. Spleen size varies greatly (which is why we measure it via ultrasound) and is not correlated to body weight (small horses can have large spleens and vice versa) so manipulating the red blood cell numbers is probably more effective in those horses with smaller spleens.

Additionally, use of "pure" EPO effectively turns the blood into "sludge", making it very thick (which is why cyclists used to get up in the middle of the night and exercise so that their blood didn't pool and cause cardiac arrest) and this blood thickening is also what Lasix does to the blood to a lesser degree making the combination of both in isolation a very unlikely occurrence as it would quite easily cause cardiac issues for the horse at exercise and even at rest. Where the "smoking gun" lies for those that believe that nefarious practices are being undertaken is the appearance of diphacinone and brodifacoum, both anticoagulants, in two of the reported deaths. The main reason that an anticoagulant would be used is to counter the "sludge" effect of a procrit/EPO/ITPP/AICAR and to be frank there is very little use of an anticoagulant otherwise.

The fact that diphacinone and brodifacoum has appeared in the post mortem report on two horses, but not all, is highly concerning. In Thoroughbreds there has long been a suggestion by those "in the known" that following the deaths of a couple of quite prominent horses in the early 2000's from heart attacks suspected from EPO use, and the work of Racing commissioners like Frank Zanzuccki whose out of competition testing in New Jersey for one changed the paradigm of use, those that were using EPO took the lead from cycling – which is essentially where EPO use began and was refined – and have reached a stage that renders normal testing nearly impotent via micro-dosing.

Micro-dosing involves using a fraction of the full dose of procrit/EPO/ITPP/AICAR, on a more frequent basis. The net effect of this consistent but smaller use is that the horse gets some of the physiological effect when it trains, and the metabolic signature of the synthetic is undetectable (you'd need to add the anticoagulant in racehorses because of the additive thickening effect of lasix). This type of "treatment" is just on impossible to detect in the cycling world where out of competition testing and "blood passports" are the norm (they have developed a test for this earlier this year but it is still not perfect and relies on an initial blood passport). In the thoroughbred world, where out of competition testing varies depending on the state that you are in, and many of the states not having the equipment that makes detecting EPO/ITPP/AICAR use possible (nor the legislation or funding required for adequately testing for it), micro-dosing of these substances and others can continue unchecked. This may be a possible explanation as to why the necropsy reports for the two horses with anticoagulants in their system, were able to note suspicion but not confirm association with an apparent coagulopathy in their deaths.


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