Re: RC: Re: Long holds, Heart Rate, tying up, electrolytes

[Tivers@aol.com]

In a message dated 12/21/99 11:09:19 PM Pacific Standard Time, 
dleblanc@mindspring.com writes:

<< 
 This is what I did my research on while in my first bout of graduate
 school.  You can model heart rate as being part of a non-linear feedback
 system.  If you take a Fourier transform of the beat to beat heart 'rate'
 (r-wave to r-wave), and sort out the component frequencies, what you find
 is that underlying the base heart rate, there are slower waves that follow
 the respiratory rate, oscillations in blood pressure, p02 waves, and body
 temperature.  Mammals use their heart rate to regulate all of the above,
 and in the case of respiratory rate, it tends to drive heart rate.  This is
 why you can bring your heart rate down after strenuous work by consciously
 lowering your respiration rate.  Unfortunately, blood pressure, oxygen
 level, and body temperature don't tell the whole story.  There's a lot of
 other systems involved, too.>

Like emotions. And in the horse, the spleen. so far, everything you're saying 
is making sense, except, of course, the quadratic stuff--I'm a dismal failure 
at calculus.
 
 >So the bottom line is that heart rate is an extremely complex, non-linear
 system.  Non-linear (for the many non-mathematicians here) means that for
 the same set of inputs, you can obtain more than one set of results.  This
 makes things extremely hard to analyze, and most physicians (whether
 working on humans or animals) don't have the engineering training to
 properly analyze the systems involved.  Even with an engineering
 background, and lots of data, there are still a large number of cases that
 aren't fully explained with even the best of data - and I'm talking what
 can be obtained in a hospital, not what can be pulled in the field.  This
 makes research on horses a lot more difficult.>

And adds another group of variables, especially when talking about recovery 
heartrates.
 
> When confronted with a non-linear system where you're not sure that you
 even have all the causal parameters, and some of your inputs appear to be
 stochastic in nature (random), even the best scientists are likely to
 resort to empirical methods.  For example, we design aircraft that way -
 even though aerospace engineering is much more of a science than horses
 are, there's still quite a bit of it that is just based on testing and
 seeing what works. >

What I call "applied research". Or "what works is real".

> Same sort of thing happens a lot in things like
 wastewater treatment - we use bacteria, and a monoculture under ideal lab
 conditions can be modeled quite precisely.  But  a real treatment reactor
 with varied input streams doesn't model all that well, and even a PhD does
 well to listen to the plant operator.  The operator may not understand the
 Monod equation, or have studied microbiology, but he does know how to make
 the plant work.
 
 In fact, the very idea that anything more than a trivial system can be
 explained using deterministic methods is considered outdated.
 
 Although I think the sport could seriously benefit from some dedicated,
 scholarly research, unless we're all willing to stop riding until the
 scientists do have a better handle on what's going on, we're stuck just
 doing the best we can with what we can determine in the field.  Heart rate
 is a good surrogate for a lot of parameters, and will tell you a lot of the
 time whether an animal is exhausted (we're talking mammals here).  The
 problem is that there are many other cases that heart rate won't explain,
 and too many times that animals surprise us with what they do.>

And there are at least several environmental factors that can move the 
heartrate around enough, and at such magnitude, to make it meaningless for 
reading other parameters accurately. For example, the "lameness" effect is 
minuscule compared to the "emotional" artifact. No one knows what the impact 
of the "just got my glucose peak" effect is. Circadian rhythms, sunshine vs 
dark skys, fear, competitive spirit, experience, dozens of metabolic factors, 
  
 
> The problem isn't limited to horses.  Bicyclists have been known to win
 races, fall off their bikes and die of exhaustion.  You can probably find
 examples in other sports where long-term exertion occurs.  Why one person
 dies when the one right behind them doesn't is a mystery.
 
 So what it all comes down to in the end is that we've only got some pieces
 of the puzzle, and we have no better alternative than to rely on people's
 intuition - this often works better than science does when you have a lot
 of unknowns.  Exhaustion is going to be a function of the individual, heart
 rate, hydration, several enzyme levels, diet, and even attitude.  I'm all
 for giving vets better tools to do their jobs with, but dismissing years of
 real-world experience just isn't realistic. >

But whose real world experience? Take Valerie Knavy as an example. She's 
competitive. She wins a lot of races. She trains and races her horses hard. I 
just experienced an important race where the participants knew which vets to 
use to pass the vet check. it was a beauty contest, for all intents and 
purposes. If I was King Soloman in a case where Valerie came into such an 
envronment, I'd tend to trust not only Valerie's judgement, but her motives, 
over those of the checking vets. 
 
Still, your point is well taken. Maybe there should be a test for the test 
vets. Gikve them a ride where they have no control, but have to predict which 
horses can safely go on and which can't, using whatever tools they have at 
their disposal. And then, everybody goes on unless the rider feels it 
necessary to stop. then you tally the number of horses that crashed with vet 
approval vs those that kept going despite vet disapproval. Do it enough times 
and you can discover the three vets in the world who actually know what 
they're quacking about.

ti 
 
 David LeBlanc >>


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