Re: RC: heat tolerance conditioning

["Beth Glace" <lb@nismat.org>]

Hi Steph,
it appears to me that horses respond similarly to humans when 
acclimated to heat stress.  Training effects are seen within 2 weeks, 
and most studies acclimate for 3 weeks.  In humans, I've seen 
studies which show that this can be done by, just as you suggested, 
overdressing while training, thus raising core temperature while 
exercise above what would otherwise have occured. Perhaps you 
could NOT clip, or use a riding sheet to increase thermal stress a bit? 
 The primary adaptations appear to be an expansion of plasma 
volume, onset of sweating at a lower body temperature [start 
sweating sooner], and a decrease in the electrolyte concentration of 
sweat.  You can go to:
jap.physiology.org and access all articles published in that journal, 
abstract or full text.  The big names in this area of research are Geor 
and Marlin, so you can search on the authors names on Medline or 
the JAP sites, or by topic.
Good luck,
Beth Glace, MS
Research Assoc.
Nicholas Inst. Sports Med. and Athletic Trauma
NY, NY

> I know ... this is not exactly a normal topic for January
> discussion! But - I would love to hear some dialogue on conditioning
> for heat tolerance. My horse, Khruschev, made the invite list for the
> Emirates World Cup - to be held in UAE, March 22. (also Darolyn and
> Albanet? Leo and Orfeo? Rita and Cass?). It's going to be quite hot
> for the race. We'll be shipping to UAE one month before the race, so
> the horses will at least have 3+ weeks to acclimate. Meanwhile, we're
> training in winter desert conditions - terrain is ok for riding
> year-round, but it is quite cold right now- rarely above 40 degrees.
> Probably won't change a lot between now and late Feb. when we ship.
> 
> Questions - any idea how long it actually takes for a physiological
> response to heat stress? Surface capillary proliferation? This horse
> is fairly large bodied, and heat dissipation is a big concern. How
> much conditioning response can I expect? Those of you who may have had
> to deal with this before (Leo?) - are there any tricks that you felt
> helped? Training with a polar fleece blanket?? Clip and blanket
> heavily at night? Or do I want to encourage him to overheat with his
> heavy winter coat?
> 
> Last year I spent 6+ months conditioning for the WEC (hot and
> humid conditions) - I felt that we were well prepared. At this
> point we're looking at about 8 weeks, 4 of those weeks being
> spent in the NW. 
> 
> Tom - you probably know the conditions in UAE in March better
> than anyone. What can we expect? How can we prepare?
> 
> Steph 
> 
> (I'm sending this post to both Ridecamp and Horsescience - and
> intend to share responses with both. I personally find them
> to be very complementary lists for endurance competitors - the
> science, and the management/training issues)
> 
> 
> 
> 
> 
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