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HYDRATION
shrivelled skin, sunken eyes and dim vision, painful urination, numb skin, muscle spasms & delirium.
There is no question that proper hydration (fluid and Intravenous therapy may be required.
electrolyte balance) is a pre-requisite for optimal sports Risks of overhydration
performance. Research has shown that athletes who do Overhydration and hyponatraemia may occur in ultra- not drink anything during exercise will perform less well endurance events lasting longer than 4 hours as a result of than they would if they drank ad libitum. However this 3.During exercise start drinking early and the over-consumption of fluid diluting the body’s sodium must not be interpreted as drinking as much as possible – levels (exact mechanisms still under investigation).
as this has not been shown to further improve replace 80% of sweat losses). This will maintain Specialized sports nutrition strategies are essential for performance and may in fact be fatal (see over-hydration).
gastric volume and increase fluid absorption these types of events and may include the addition of sodium as well as careful regulation and monitoring of fluid Water and electrolyte balance are critical for the function of all organs. Water provides the medium for biochemical 4.After exercise be aggressive in replacing all reactions within cell tissues and is essential for maintaining sweat losses (i.e. after exercise/training Signs: unconscious or severely confused especially when
blood volume and thus the optimal function of the replace1.5 x remaining weight loss). This is very blood glucose concentrations are normal, vacant stare, cardiovascular system. Physical exercise and heat stress important when competing in later events on cause both fluid and electrolyte imbalances that need to be the same day or the next day. Recovery of corrected to avoid the effects of dehydration. These effects significant fluid loss after exercise is assisted by Strategies to replace fluid before, during and
will vary according to the type and intensity of exercise, after exercise
the simultaneous replacement of electrolytes body size, environmental conditions including the climatic Generally athletes dehydrate during exercise because of a conditions (temperature and humidity) and clothing.
mismatch between thirst and fluid requirements. They mayalso fear weight gain or the need to urinate during the Risks of dehydration
event, or they may not have easy access to fluids during Make the most of opportunities to drink within Increases core body temperature and the body the confines of the sport (e.g. stoppages, injury 1.Begin exercise in a well-hydrated condition.
Increases the strain on the heart, as the heart Use all opportunities to drink before even Individually labelled bottles should be readily rate increases for a given workload.
exercising (e.g. meal- and snack times, in available, not in a tog bag left in the change Perceived effort is greatly increased and transit, at work or at school). Athletes can learn concentration, skills and mental functioning is to tolerate up to 5ml fluid/kg body weight in the Fluid should be served in containers that allow adequate volumes to be ingested with ease and Rehydration is much more difficult to achieve because of the subsequent gastro-intestinal 2.Don’t rely on thirst. In general thirst is not Coaches, trainers, parents must encourage full perceived until an athlete has already lost 2% of body weight. A fluid replacement plan should Fluid intakes of children, the elderly, pregnant Early signs of dehydration typically experienced
requirements and needs to be practised in include:
headache, fatigue, loss of appetite, flushed skin, heat intolerance, light-headedness, dry mouth and eyes, dark Advanced signs of dehydration require urgent medical
attention such as difficulty in swallowing, clumsiness, THE IDEAL DRINK
500 mg of caffeine is consumed within a short period (although this may vary between individuals). Always 1. Carbohydrate: Type and amount –
check labels of drinks for any other substances, some of (concentration)
which may be counter productive or even banned. The addition of carbohydrate to the ingested fluid willenhance performance even further than water on its own.
4. Palatability
Preference should be given to drinks containing glucose or This includes flavour, taste, mouth-feel and temperature glucose polymers, rather than fructose since fructose and may have a large impact on voluntary fluid intake.
during exercise delays gastric emptying and so decreases Drinks should be cool (15-22C) and palatable for the the rate of fluid absorption. Furthermore excessive individual – note taste does change during exercise and if fructose may increase the risk of diarrhoea and fruit juices a drink is unacceptably sweet during or even after are therefore not recommended during exercise. exercise, experiment with other drinks or consider a lowerconcentration adding unflavoured glucose polymer The amount of carbohydrate in the drink (concentration) can be varied according to individual needs andenvironmental and climatic conditions. When carbohydrateneeds are more important, a higher carbohydrateconcentration not exceeding 10% (greater concentrations delay gastric emptying and may cause diarrhoea and stomach cramps) or 60g carbohydrate/hour will be of benefit. In extremely hot conditions when fluid needs take priority, a more dilute solution of 4% carbohydrate 2. Electrolyte composition and concentration
Sodium and potassium, the main electrolytes lost through sweat are found in limited amounts in most commercial sports drinks. Too much sodium affects the taste of the drink and so the amount of sodium in drinks (10-30 mmol/l) only partially replaces sodium lost in sweat(ranging from 10-90mmol/l). Foods and snacks with a high salt content are therefore recommended to make up 3. Other active ingredients
All rights reserved. No part of this publication may be reproduced, stored in Sports drinks generally don’t need to have added vitamins a retrieval system or transmitted, in any form or by any means, electronic, as losses via sweat are low. However optimal intakes of mechanical, photocopying, recording or otherwise, without prior permission vitamins and minerals should still be met. Caffeine and of the South African Sports Commission.
caffeine-like substances may be present in some drinksand these drinks should be discouraged particularly in the post exercise recovery period since caffeine has a diuretic Printed in South Africa by SILOWA PRINTERS effect. Note that a urinary caffeine concentration above > Design and layout by JOY DESIGNEditing by SASC accredited dieticians 12µg/ml-1 is considered as doping and may be achieved if

Source: http://www.sanaa.org.za/resources/hydration.pdf