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The Effects of Dehydration in Martial Arts
'Making the Weight' -
The Effects of Dehydration on
Physiological Functioning.
During prolonged exercise in hot
environments, water losses of up to 3 litres per
hour have been reported, with 90 percent of
this total loss occurring through
sweating (Wilmore and Costill, 1994). For the
fighter struggling to make their
weight, a litre of sweat lost in the
sauna/steam-room or through exercising in sweat
kit will be "rewarded" with approximately 1
kg of lost body weight.
This may seem an attractive prospect as the fighter tries to make their weight, however in order to facilitate optimal physiological functioning, the body's water and electrolyte content should remain relatively constant. Many investigations have been carried out to study the effects of dehydration on physiological function.
Dehydration has been shown to reduce blood
and plasma volume, this results in a
decrease in the amount of blood pumped out by
the heart, consequently the heart has
to work harder in an attempt to maintain an
adequate blood (oxygen) supply to the
working muscles (Robergs and Roberts, 1997;
Clarkson, 1998). Dehydration has been
shown to decrease testosterone levels (Booth
et al., 1993; Viscardi, 1998), increase
blood lactate accumulation (Wilmore and
Costill 1994), and impair the body's ability
to sweat, resulting is an increased risk of
overheating. (Armstrong, 1992; ACSM,
1996).
Armstrong (1992, p.29) suggests, "Dehydration
results in reduced muscle blood flow,
waste removal, and heat dissipation, all of
which are necessary for sustained, high
power muscle action in events such as boxing
and judo."
Taken to the extreme, rapid weight loss when
achieved through dehydration can be
fatal. Viscardi (1998) identifies that
excessive dehydration can harm bodily
functions, leading to kidney failure, heat
stroke or heart attack, indeed in 1997,
within a period of thirty-three days, three
young American wrestlers tragically died
whilst trying to 'make their weight'
(Hickling, 1999).
Does re-hydration work?
After completing the weigh-in, fighters
typically try to rapidly replace lost body
fluids in an attempt to return to a normal
state of hydration. However, the fighter
is unlikely to eat and drink sufficiently
because of the negative effects of
fighting on a full stomach. In many cases the
time between the weigh-in and first
contest is usually insufficient for fluid and
electrolyte balance to be fully
re-established in muscles, or for the
rehydration and replenishment of muscle and
liver glycogen (ACSM, 1996; Yankanich et al.,
1998; Clarkson, 1998). Horswill et al.
(1990, p.470) state, "The period between the
weigh-in and competition is probably
not enough time for wrestlers, boxers, and
judo athletes to replace muscle
glycogen." This is supported by Foster (1995,
p.66) who identified that "The body
takes from 4 to 48 hours to fully recover
from moderate dehydration, which means
there isn't enough time between weigh-in and
the match to ensure peak performance
and health."
References:
American College of Sports Medicine. (1996).
"Position stand: Weight loss in
wrestlers." Medicine and Science in Sports
and Exercise. 28. pp.ix-xii.
Armstrong, L.E. (1992). "Making weight in hot
environments." National Strength and
Conditioning Journal. 14 (5), pp.29-30.
Booth, A. Mazur, A.C. and Dabbs, J.M. (1993).
"Endogenous testosterone and
competition: the effect of fasting."
Steroids. 58 (8), pp.348-350.
Clarkson, P. Manmore, M. Oppliger, B. Steen,
S. and Walberg-Rankin, J. (1998),
"Methods and strategies for weight loss in
athletes: A round table." Gatorade Sports
Science Institute. 8 (1), pp.1-9.
www.gssiweb.com/references/
Foster, C. (1995). "The way to go when the
weight is the thing!" Scholastic Coach.
65 (3), pp.64-67.
Hickling, D. (1999), "Wrestling safely with
weight loss." Foster's Daily.
http://www.fosters.com/sports99/january/10/sp0110a.htm
Horswill, C.A. Hickner, R.C. Scott, J.R.
Costill, D.L. and Gould, D. (1990). "Weight
loss, dietary carbohydrate modifications, and
high intensity, physical performance."
Medicine and Science in Sports and Exercise.
22. pp.470-476.
Robergs, R.A. and Roberts, S.O. (1997).
Exercise Physiology: Exercise, Performance,
and Clinical Applications. Mosby (London).
Wilmore, J.H. and Costill, D.L. (1994).
Physiology of Sport and Exercise. Human
Kinetics (Champaign IL).
Yankanich, J. Kenney, W.L. Fleck, S.J. and
Kraemer, W.J. (1998). "Precompetition
weight loss and changes in vascular fluid
volume in NCAA Division 1 College
Wrestlers." Journal of Strength and
Conditioning Research. 12 (3), pp.138-145.
by: by Dave Coles MSc BA (Hons) PGCE, (the combat academy)
Article date: November 2006.