'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,
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
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."
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.