Thoroughbred racing science offers an alternative in the form of a conditioning programI know that I promised last month to delve into muscular fatigue this time around, but that subject is going to have to wait until next month. Instead, there is more news involving a bigger problem: bleeding.
You will remember that last month we talked about some studies demonstrating a preferential shunting of blood into the areas of the lungs of quadrupeds, where bleeding typically begins in Thoroughbred racehorses. High and to the rear of the lungsto combat the effects of gravity, the scientists thought. I guessed then that this science may just show us a glimmer of light at the end of the tunnel, as far as the waste involved in Thoroughbred bleeding is concerned. Now, more new science offers even more hope, along with an explanation as to why some trainers around the world do not seem to encounter bleeding problems to the extent that we do in the United States.

Causes of bleeding
For at least a decade, our own research has focused on the causes of bleeding in our racehorses and the efficacy of drugs like furosemide (Lasix) in eliminating the problem. There have been all sorts of fatalistic pronouncements suggesting that we are breeding animals that cannot handle the rigors of racing, that Thoroughbreds are destined to bleed because that is the nature of the demands of the task, and that the best we can do is lessen the impact of bleeding with drugs that reduce blood volume while they introduce another set of negative side effects.
In the August, 1995, issue of Medicine and Science in Sports & Exercise, the American College of Sportsmedicine (ACSM) published a series of papers concerning the control of blood flow within major vessels and small capillaries (microcirculation). A couple of the papers dealt with what happens before and after a conditioning protocol designed to enhance cardiovascular efficiency. The consensus of these findings was that, with minimal cardiovascular conditioning, the vasodilation of the major blood vessels in response to exercise demand is rapidly developed, but a similar efficiency in the microcirculation requires a much more extensive conditioning process.

Heart rates
This is another very important piece of the puzzle. Picture this: At the beginning of the race, the Thoroughbreds heart rate revs from a resting rate in the mid 30s to over 220 beats per minute in a few seconds. Within the first quarter mile, red blood cells density will nearly double as the spleen contracts. If these cells have been sequestered in the spleen for five days or more or, if anytime in the past 60 days or so the spleen had been allowed to remain dormant, then there is a strong possibility that echinocytes have formedred cells that do not bend and squeeze through small blood vessels very well. If the horse has had jugular injections, aggregations of cells, as well as other debris, will also be present in the blood. Clearly, the horse needs all the shoulder room it can get in its microvasculature.
The minimally conditioned Thoroughbred (all are minimally conditioned when compared with their human counterparts) will be able to dilate his major blood vessels quickly and significantly, while the microvasculature will not attenuate as rapidly or as completely. At the same time, all this extra blood pressure, thickness, and debris will be shunted preferentially to the areas of the lung we know as being most likely to explodeas a garden hose would explode when confronted with the pressures experienced by the Alaska pipeline.
The ACSM studies also demonstrate that whatever vasodilation is available to the athlete occurs in response to the pressures the blood vessels experience at the onset of high intensity exercisered blood cells rubbing on the walls of the vessels, for example. Think of this: Only a very few Thoroughbreds warm up properly just before a race. There are dozens of reasons why a high intensity warm-up immediately before the race will protect the animal and enhance its performance during the racewarm, flexible tendons, ligaments, and muscles, improved agility in the stride, catacholamine (adrenaline and noradrenalin) production, splenic contraction and a doubling of the red blood cell count before the gate opens, fuel and enzyme mobilizationand now we have another: peripheral vasodilation and the possible prevention of bleeding.
The warm-up must be strong enough to cause the spleen to contract and the heart to rev up pressure if the endothelium of the small blood vessels is to be irritated enough to produce the nitric oxide and bradykinins that will trigger blood vessel relaxation. That means heart rates at or above 195 for at least a quarter mile. Ideally, the muscles, tendons, and ligaments of the animals will have been warmed and stretched by significant slower work within a couple hours of the race.

Proper warm-ups
Proper warm-ups in Thoroughbreds, I am afraid, are the bailiwick of those few with the courage and intelligence to face the criticism, pay the freight, and perform the extra work in order to reap the benefits of improved performance and lowered risk of injury. They stand out in the post parade. Bet them as if they are an overlay and you will make a little money. A properly warmed-up horse, even one that breaks through the gate and has to be chased down for a restart, has just injected himself with a group of homemade drugs more potent than any needle smuggled in from Europe or Canadaand far safer.
What science tells us about cardiovascular exercise in humans is that in order for sedentary humans to meet minimum criteria for cardiovascular fitness, a long-term conditioning program that delivers a half hour of continuous, 60% heart rate exercise two or three times a week is necessary. Every heart patient in the country knows this. In order to generate a 60% heart rate in a Thoroughbred, the animal must be galloping at about a three-minute lick, depending on the fitness and efficiency of the individual. A half hour of three-minute miles is how many continuous miles? And how many three-minute miles can your horse do today? How many continuous three-minute miles will your equine athlete ever be able to do at the rate his training is progressing?
The kind of conditioning program the ACSM scientists are talking about, though, goes far beyond that which is intended to keep middle-aged men from dying of heart attacks. Cardiovascular fitness in human athletic terms means something far different than it means when uttered by a trainer of a Lasix-aided Breeders Cup entry. The 100-plus strenuous miles the human middle-distance athlete delivers each week are the equine equivalent of 200 miles. Indeed, due to the equine spleen, cardiovascular challenge is even more difficult to induce in the Thoroughbred than it is in the human. And the human performs a large bulk of his training at 75%-to-90% of his maximum heart ratethe equine two-minute lick.
Perhaps a conditioning protocol that begins with enough background mileage that a significant cardiovascular preparation can be achieved, followed by a substantial volume of race-specific workall with the goal of ensuring safe, maximal performance for every individual horse worth the extra effort (you already know that it is possible to eliminate the absolute nonperformers relatively quickly in the training program).

Common sense
I will leave it to you to figure out why such a concept will not be a part of our mainstream research well into the next century. There are at least a dozen reasons. And I will not suggest to you here that I have a surefire bleeding-prevention conditioning protocol. But common sense combined with known science points the way for the individual pioneer to prove to himself and his associates that better conditioning protocols can overcome a multitude of difficulties now confronting Thoroughbred horse racing. Where trainers like Max Hirsch and Federico Tesio cut the trail, and where a few European, Irish, Australian, and Englishand a very few North Americantrainers lead the way today, many of us will eventually learn to follow, and then surpass, our pioneers.
Maybe the horse is different than the humans, rats, antelope, dogs, and other animals studied by the scientists of exercise physiology around the world. Maybe we can do nothing to improve performance and drastically reduce injury and bleeding through trainingthere are many scientists, veterinarians, and trainers in our industry who would have you convinced of that.
But the way to find out is to try it, the whole thing, with a large enough group of horses that you are out of the one-rat research/anecdotal category and into genuine applied science. We can do basic research forever, but until we actually try to build genuine top quality racehorses through better applied science, we are wasting our time and resourcesgoose-chasing all sorts of dead-end causes and effects while denying the relevance of the core technology of our industry, exercise science.
Wouldnt it be shameful if applied conditioning science were to happen first in Hong Kong, Japan, or Australiawith horses whose bloodlines were developed in Kentucky?