MAXIMISING OLYMPIC DISTANCE TRIATHLON PERFORMANCE ...

If heat illness is not treated properly,serious complications can occur, suchas renal failure, arrhythmia, coma anddeath. Research has shown that in welltrained and acclimatised athletes, theheat dissipating mechanism becomesmore efficient and, therefore, adequateconditioning, together withacclimatisation and paying attention tohydration, form the key to prevention.Some athletes can cope better with heatthan others because of differences inheat generation and heat dissipation.Glycerol loading has been used toprevent dehydration but research hasshown conflicting results and significantside effects can affect any potentialbenefits [13].Hyponatraemia (waterintoxication)Hyponatraemia is now considered oneof the more serious problemsassociated with endurance exercise. Ithas been reported to occur in athletesafter long endurance events such asultra - marathons and the IronmanTriathlon [18]. Although it may beasymptomatic, hyponatraemia has beenassociated with signs and symptomssuch as altered mental status, seizuresand pulmonary oedema. The most likelycause of hypotranaemia is acombination of loss of salt through sweatand retention of high volumes ofhypotonic fluids that have been ingested.Sweat loss can be as great as 2.8l perhour.The water intoxicated athlete is wellhydrated and has a normal temperature(in contrast to the athlete with heatillness). Often the symptoms do no occuruntil a few hours after the athlete hasfinished the event. The delayed onset ofsymptoms may be due, in part, tocontinued hypotonic fluid ingestionfollowing the race and increasedabsorption of hypotonic fluids from thegastrointestinal tract after the athlete hasstopped running.Treatment of hyponatraemia is primarilysupportive and includes infusion ofnormal saline. The risk can be reducedby planning a replacement scheme thatincludes a combination of water andglucose electrolyte solutions.References1. Shephared RJ, What is the optimaltype of physical activity to enhancehealth? Br J. Sports Med 1997; 31:277-2842. Hellemans J. Prescribing exercise ingeneral practice. New ZealandMedical Journal 957: 98 (790) 19853. Kuipers H , Training andovertraining: an introduction Med.Sc. Sp.Ex 1998; 1137-11394. Kuipers H, Keizer HA. Overtrainingin elite athletes. Review anddirections for the future. SportsMedicine 79: 6, 19885. Maynard M, et al. Injuries amongstcompetitive triathletes. The NewZealand Journal of Sports Medicine2: March 19886. James SL, Bates BT. Injuries torunners. American Journal ofSportsmedicine 40: 6, 19787. Mellion M.B. Common CyclingInjuries, Management andPrevention. Sports Medicine 11(1):52-70, 19918. Hellemans J. Personal observation,January 19889. Greipp IF. Swimmers shoulder: theinfluence of flexibility and weighttraining. The Physician andSportsmedicine 92: 13 (8), 198510. Costill DL, et al. Effects ofrepeated days of intensified trainingon muscle glycogen and swimmingperformance. Medicine an Science14