Re: RC: Re: Discrete Inquiry

[Onefarmgirl@aol.com]

In a message dated 7/10/00 1:36:25 PM Pacific Daylight Time, Tivers writes:

<< New Hypothesis

Hi Tom.   Thanks for sharing this great info.  Not being an exercise 
physiologist, my comments are pretty general.  In fact, I would withold any 
input except that you seem to be opening this up for general discussion.
 
<< One of the primary adaptations seen in longterm endurance conditioning is 
greatly increased mitochondrial use of intramuscular triglycerides. Virtually 
all of the fat used during endurance competition in humans comes from this 
already-stored and efficiently-converted substrate source.  Little, if any, 
fat in circulation is used as racing fuel when carbohydrate supplementation 
is being used during the race. And, of course, adipose tissue is the most 
costly of fuels to mobilize. >>

I presume this entire graph applies to humans?  If so, using it as a 
springboard for the subsequent theory w/o validating applicability to equines 
seems to me to start you off with one foot in a bucket.   Or perhaps the 
human-equine similarities/differences in cellular energy production are 
already quite well understood?   If not, it seems you'd need to do that 
first, or proceed with much caution, since as we have seen, tiny differences 
(one enzyme) can make big differences in species.   A substance or regimen 
which is useful in one species can 
be harmful in others.

Along that same vein, even if we 'know' that the celluar energy physiology is 
the same, I think you may be making a leap about dietary supplementation and 
how it supports the substrate base.  Equine digestive processes are so very 
different from our own, that timing food sources to manipulate this system 
may likewise be different.

I guess I was a bit confused by what information in your post is data that 
you know, and which is information you are seeking to validate (or not).  For 
instance, do we know that this information

  
 "That underlying triglyceride substrate base is the key to never having to 
worry about available substrate under a carb-supplemented high-output 
competition." 

applies to equines, or is that part of the theory you are advancing?   


My other area of concern would be more pragmatic, and it's reflected in your 
question

<<  How does a shift to a primarily carb-based training diet to a fat loading 
diet affect digestion?  >>

In general the digestive processes of the equine are relatively easy to 
disturb.  Humans seem to be iron guts in comparison.   The varied dietary 
tweaking thay you suggest may have unforseen consequences in gut motility or 
nutrient absorption and transport, even if they are useful in energy 
production and availability.
 
<< And that's why I'm asking you to wrestle with this concept a little in 
your spare time.>>
 
Happy to wrestle with the concept, unable to contribute to 'field trials' 
with my one endurance horse  :-)


pat farmer