Australian Triathlete – July-August 2017

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@Drmitcha


in these protocols from forty minutes to
two hours, using walking/running/cycling
at an intensity of 40-80% VO2max. Guy
and colleagues (2016) synthesis of all
these options suggests that MTHA is
significantly more effective than STHA. For
instance, plasma volume expansion in
MTHA (7%) is double that of STHA
(3.5%). So shooting for 45 minutes daily at
50% max for two weeks should be the
target for all athletes trying to heat acclimate
properly. It’s a big time commitment, but
the performance gain is also large. The
benefit starts to decay in days to weeks, so
this is best done in close proximity to the
event. I would suggest starting at 21 days
before race day and completing with a
week to taper fully acclimated.
Regarding acclimation mode, to my
mind, cycling is the simplest to execute on
a daily basis, and the easiest to control in
terms of intensity (also minimal muscle
damage). Keep the effort low. The heat is
already stressful, and the muscles
generate quite a lot of heat at low-
moderate exercise intensity. Set up a
cycling ergo in the laundry and turn on the
clothes dryer with a wet towel inside to
provide enough heat and humidity for the
purpose. Trying to drag a treadmill into the
laundry sounds like hard work! Avoid using
a fan to allow more heat accumulation -
the idea is to get the body temperature up
and illicit heavy sweating. You will need
towels, lots of towels.
Given that plasma volume expansion
and increased sweat volume are the main
effects of heat adaptation replace fluid
and electrolytes as you go. Setting a set of
scales next to the ergo is easy. You’ll also
get a sense of sweat rate if you keep track

The real world aspect of this process
isn’t lost on me. It’s a big commitment - so
don’t worry if you miss a day or two. Aspire
to 14 sessions and consider 10 to 12 a job
well done. The idea is to be acclimated
before reaching your destination, so the
final touches of the taper are effective.
You may mix some passive heat
adaptation with the active sessions, but
keep in mind that this type of protocol
remains unvalidated in the lab. Passive
heat adaptation has been popularised
through elite cycling and involves entering
a sauna for 15-30 minutes at the end of a
training session.
Engage with the process of heat
adapting as you would any other part of
your training. There is no sense arriving in
Cairns, Hawaii or any other ‘hot’ race
course in an ill-prepared manner. As they
say, the proof is in the pudding.
So get cooking.

refereNceS

Armstrong, L E and C M Maresh. The induction and decay
of heat acclimatization in trained athletes. Sports Med. 12:
302-312, 1991.
Guy JH1, Deakin GB, Edwards AM, Miller CM, Pyne DB.
Adaptation to hot environmental conditions: an
exploration of the performance basis, procedures and
future directions to optimise opportunities for elite
athletes. Sports Med. 2015 Mar;45(3):303-11.
Santiago Lorenzo, John R. Halliwill, Michael N. Sawka,
Christopher T. Minson Heat acclimation improves
exercise performance Journal of Applied Physiology
Published 1 October 2010 Vol. 109 no. 4, 1140-1147
Willmott AG, Hayes M, Waldock KA, Relf RL, Watkins ER,
James CA, Gibson OR, Smeeton NJ, Richardson AJ, Watt
PW, Maxwell NS. Short-term heat acclimation prior to a
multi-day desert ultra-marathon improves physiological
and psychological responses without compromising
immune status. J Sports Sci. 2016 Dec 9:1-8.

of this each day- letting you know that
adjusting to the heat is taking place.
Additionally, this will allow you to
approximate your sweat rate on race day
and the fluid required to match sweat
losses. Another easy measure is body
temperature - pop a thermometer under
your tongue while you are weighing in. A
steady drop should occur over the two
week period (anywhere from 0.5-1C).
As a practical note, athletes should be
cognisant that plasma cortisol (stress
hormone) is stimulated by exercise in the
heat. Cortisol is a reliable indicator of
strain on the body. Erring on mild doses of
heat exposure are therefore
recommended in the tapering athlete. The
whole purpose of the taper is to reduce
stress on the body and allow it to
recover- blunting this recovery with
high-intensity heat training would be
counter-productive. Stick to the lower
ends of the recommended intensity and
use the daily dose as an adjunct to other
sessions, rather than an ‘extra’ load.
Concomitant reduction of the swim and
run session volumes to match a ‘regular’
taper volumes should also alleviate some
of the time and physical stress associated
with the addition of heat acclimation.

@DrMitcha


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@Drmitcha


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