Re: Carbo loading products

[Susan Evans Garlinghouse <suendavid@worldnet.att.net>]

Tivers@aol.com wrote:

> Great calculations--came out to almost exactly what I said the carb/fat
> burning ratio would be. Most of the rest of the energy would be provided by
> FFAs, of course. However, a periodic carb boost can do no harm and might
> prevent fatigue and injury, as well as delivering better performance.

I agree!  Anything that will safely top up the gas tanks during a ride
sounds like a great idea to me, and I think the increasing experiences
being reported back from people using it are showing it is safe, used
intelligently (and I wish more people *would* post publicly about it.)



> You're missing the point. I'm not, and never have, talked about attempting to
> deliver ALL the working energy via carbs. That would be as dumb as attempting
> to deliver ALL the working energy via FFAs. There is a significant part for
> both--and hopefully thos bases are covered before much in the way of protein
> is catabolized.

OK, than somewhere along the way I thought you were advocating trying to
influence the energetic pathways to rely as heavily as possible on
glycogen, which we both agree isn't practical.


> Well, you're making some broad assumptions there. Concerning initial
> carbohydrate availability, digestive efficiency, appetite, etc. 
Without
> sufficient blood glucose, FFAs will be preferentially used, disabling a good
> proportion of the available carbohydrate. Fat is intended for low energy
> work--and that is what you get--a low energy horse. The occasional dose of an
> easily absorbed carbohydrate ensures the use of available carbohydrates.

Sure---but endurance is a relatively low energy exercise on a
minute-by-minute basis, at least compared to horses in your world.  The
big energy bill for endurance horses adds up because they do it for so
long, right?  So FFAs *should* be preferentially used for the bulk (ie,
65%) of the work, simply because they're in almost endless supply, and
conserve the glycogen to keep supplying the pyruvates for ATP turnover,
and hopefully, provide an extra kick of rocket fuel when needed and when
the FFAs *won't* be helpful.


> Glucose levels are never consistent--they're all over the place. What you mean
> is a sustained elevation of blood glucose as opposed to hypoglycemia.

Yes---and also sparing liver and muscle glycogen stores as possible,
especially during multiday rides.



> Have you ever seen the muscle biopsy studies demonstrating that a horse can
> work for hours, come back exhausted, and still have nearly 100% of the initial
> glycogen content in FT muscle cells--it's a horse study, one of the early
> ICEEPs, Sweden or San Diego.

Depending on the type of exercise, that's not too surprising---sustained
endurance type exercise will preferentially deplete the slow twitch
fibers with little depletion occurring in the FT.  During hard, intense
exercise, it'll be the other way around.


 Bursts of speed, or aggressive hill climbs can be
> very benefical in the endurance horse, mobilizing that glycolytic pathway and
> providing a lactic acid cascade to the oxidative pathways for additional,
> fast-acting fuel.

Well, I'm not sure I want to rely on lactates as a fuel source too much
during a ride, simply because overdone, you're also disrupting the
cellular environment and compromising immediate performance, a bigger
issue than providing another fuel source.  But I have no argument with
using fartleks during training to condition the FT fibers, as long as
it's not done so much as to start to influence the type IIA fibers.

> >  But, I think ignoring the horse's basic energetic physiology
>  and forcing him to rely on glycogen as a primary fuel sounds pretty
>  penny wise but pound foolish to me.  At least for distance horses.>
> 
> Pretty foolish to me, too. Who said that? What I said was that glycogen had to
> always be available in significant quantities and that blood glucose should
> remain significantly above fasting levels. This is easy to achieve with
> periodic feedings of easily absorbed carbohydrate.

Then we're agreed.

Have a good trip.

Susan G
> 
> 
>  >
>  > By the way, on your recommendation I did get Lon Lewis' latest book. Still
> a
>  > pretty bright fellow and certainly not in love with fat. I'll pull some
> quotes
>  > for you when I get back.
> 
>  I'm surprised to hear you say that---his in-depth discussions of fat
>  supplementation for equine athletes seems to pretty strongly support it
>  for numerous reasons.  Quite clearly and succinctly.>
> 
> I'll endeavor to get some clear and succinct quotes for you when I return.
> 
>  >
>  > Meanwhile, you can only deny your own experiences for just so long before
> you
>  > realize that something's wrong with your calculations. What's wrong is the
>  > underlying premise.
> 
>  >Well, as always, we may just have to agree to disagree---I agree that
>  carbohydrate supplementation is helpful to some horses...but the
>  operative word there is *supplement*.  The hard numbers just don't
>  reasonably support your theory in practical application.>
> 
> You consider 2 ounces every 2 hours to NOT be a supplement? You're not even
> attempting to understand what I'm saying.
> 
> ti
>