Endurance.Net Ridecamp Archives

In a message dated 8/10/2005 5:45:05 AM Pacific Daylight Time, G1BASS@xxxxxxxxxxxx writes:

> With all the excitement about Lance Armstrong's 7th winning of the Tour de France (he uses an altitude simulator), and the success of Kenyan runners in sea level competition. Does anyone see a possible correlation between horses and humans when it comes to elite performance and training at simulated altitude or use of Intermittent Hypoxic Treatment, even when taking into account the horses splenic mechanism?
>   
> Here is Dr Wickler of Cal Poly's paper on  Hematological changes and athletic performance in horses in response to high altitude (3,800 m)
>  http://ajpregu.physiology.org/cgi/content/full/279/4/R1176
>   
> comments or insights?
>   
> G


It is true that altitude simulation (or altitude) will stimulate the production of the hormone erythropoeitin (EPO), which, in turn, stimulates the production of red cells. You can buy a $35,000 machine to do simulate altitude in horses and achieve this effect. Or you can use any one of a numberr of verrsions of the hormone itself that are illegal, but undetectible. 

The efficacy of any of these approaches in the horse is not as good as in humans because there is a small window of benefit to performance. The equine spleen has the capability of sequestering up to 50% of the animal's red cells, then injecting them into the blood stream at the onset of strenuous exercise. So a resting PCV of 40% might become a working PCV of 55 or 60%.

Rheologists say that in the equine, a PCV of 66% is the "sludging" threshold, where blood begins to take on the viscosity and flow rate of toothpaste. there are many negatives to that kind of situation, including poor performance, small capillary clogging, large blood vessel clogging, heart attacks, cartilage degeneration, etc. 

In my experience, at a resting PCV of near 50%, a decrement of performance is seen in the racehorse. No doubt, health is beginning to be impaired at that point as well.   

There has long been a fixation on red cells in the horse. As the horse becomes more fit, the spleen enjoys a continuing increase in capacity. So, over time, a trainer might see resting PCV drop from, say, 43% to 33%. this observation tends to cause hysteria in those who don't know what's going on and a variety of treatments for anemia are often implemented, most completely ineffective for that purpose. With the advent of illegal but undetectabloe EPO, this 'problem" is solved on the racetrack.  My guess is that it will soon be in elite endurance horses as well. 

You can make all the rules that you want, but if they cannot be enforced, or if you don't enforce them for political reasons, it's an exercise in futility. 

ti