HYDRATION DURING SPORTS COMPETITION
Posted by Dr. Nagaraj Pushparaj on Sunday, 21st June 2009
Hydration for Optimal Sports Performance
Proper hydration is essential to peak performance in every sport, not just endurance events.
Why? Because a poorly-hydrated athlete not only suffers from a deterioration in speed or strength, but from impaired motor skills too.
Having the correct hydration strategy is as important to football players fighting off their opponents’ repeated attacks in the dying minutes of a soccer match, as it is to marathon runners and road cyclists seeking to prevent cramps and heat stroke in the final miles of a race. After all, it only takes one late goal to lose that all-important game…
The problem for athletes and coaches is this: much of the accepted wisdom about hydration has come under the spotlight in recent years, with leading sports scientists disagreeing about some of the most fundamental tenets of fluid balance and refuelling.
Take the renewed debate over the ‘official’ advice given to athletes wishing to maintain optimum hydration – that they need to make sure they drink enough to replace all the fluid lost in sweat during endurance events. Australian researchers have called on the American College of Sports Medicine and other official bodies to revise their current fluid replacement guidelines in the light of recent research that suggests even quite large fluid losses don’t necessarily lead to dehydration or heat illness.
Meanwhile Tim Noakes, the renowned exercise physiologist, has argued in a hard-hitting leading article in the British Journal of Sports Medicine that the case against ‘over-drinking’ was proven over 20 years ago – and that official advice has been unduly influenced by the marketing needs of the worldwide sports drink industry.
Given the rethinking on hydration amongst sports scientists, what are the rest of us ‘mere mortals’ to make of it all? After all, whether you’re a serious athlete, or coach, you’ll want answers to these, and other key questions:
Exactly how much should you drink – and when?
Can you over-drink – and if so what are the likely consequences?
At what point does dehydration start to really impair sports performance?
What kind of sports drink is best – and which ones are a waste of your time and money?
Should the kind of sport you perform dictate the kind of sports drink you consume?
How does your diet affect your hydration needs?
Hydration for Optimal Sports Performance has been put together by Andrew Hamilton, Editor of Peak Performance newsletter and himself a qualified sports nutritionist and former competitive triathlete. ?
What’s the best half-time refuelling strategy in team sports like soccer, rugby and basketball?
Details of a new carbohydrate drink that could give a clear endurance advantage over your competitors!
What’s the secret of ‘hyper-hydration’ – and how can you successfully take advantage of it?
Caffeine & Alcohol: why is one of them good for you – and the other to be avoided if all possible?
Why is adequate hydration of particular importance to strength & power athletes?
Designing an Individual Hydration Strategy – how do you work out what’s right for you?
There is increasing scientific dissatisfaction with the ‘official advice’ that’s been published by such organisations as the American College of Sports Medicine (ACSM) and the International Marathon Medical Directors Association (IMMDA).
The ACSM guidelines for endurance athletes recommend that ‘During exercise, athletes should start drinking early and at regular intervals in an attempt to consume fluids at a rate sufficient to replace all the water lost through sweating (ie bodyweight loss), or consume the maximal amount that can be tolerated’.
The IMMDA, meanwhile, has recommended a fluid intake of something between 400 and 800ml per hour, with the higher rates being appropriate for faster or heavier runners and the lower rates for slower runners and walkers.
The problem with both sets of recommendations is that they are too inflexible. The ACSM guidelines can be interpreted as encouraging runners to drink as much as they can: this may be more than is necessary and can lead to problems of water overload and even hyponatraemia (a potentially dangerous fall in the blood sodium level).
Even at the narrower range set by the IMMDA, 400ml will not be enough for a heavy runner on a hot day, while 800ml is likely to be too much for a light runner taking five hours to complete a marathon on a cold day.
The only sensible advice is for individual athletes to take personal responsibility for developing their own hydration plan. The question is, what’s the right way to do this?
So ,how best to construct your own individual hydration strategy, depending on your body weight, gender, the type of sport you play, weather conditions and other essential factors.
Everything you need to make sure your hydration strategy is right for you.
Sports Drinks vs Plain Water – how do you achieve the optimal fluid balance?
A comprehensive hydration strategy involves ensuring the appropriate fluid intake before training/competition, maintaining it during exercise and then replacing any shortfall as soon as possible afterwards.
However, hydration isn’t just about water: fluid loss via urine and, especially, sweating involves the loss of electrolyte minerals – calcium, magnesium, sodium, potassium and chloride.
There are three reasons why replacing these minerals by means of an electrolyte mineral-containing drink may be better then drinking pure water alone:
Although the amounts lost in sweat are generally small in proportion to total body stores, prolonged heavy sweating can lead to significant mineral losses (particularly of sodium). Drinking pure water effectively dilutes the concentration of electrolyte minerals in the blood, which can impair a number of normal physiological processes. An extreme example of such an impairment is ‘hyponatraemia’, when low plasma sodium levels can be literally life threatening.
Drinks containing electrolyte minerals – particularly sodium – are known to promote thirst, thereby stimulating a greater voluntary intake of fluid. There is also evidence that drinks containing sodium enhance the rate and completeness of rehydration after a bout of exercise.
When the electrolyte minerals – again, particularly sodium – are present in appropriate concentrations, the rate of fluid absorption from the small intestine into the rest of the body appears to be enhanced, especially in conjunction with small amounts of glucose. This is particularly important when rapid uptake of fluid is required, such as during strenuous exercise in the heat.
Because properly formulated carbohydrate/electrolyte drinks can and do increase hydration (and, as a bonus, supply extra carbohydrate to working muscles), it’s hardly surprising that they really do enhance performance when fluid loss is an issue.
But what’s the best strategy for individual athletes? And how do you decide on the best drinks for you?
Take the renewed debate over glucose polymers versus pure glucose – which is best for athletes, and why? Or the argument over fructose vs glucose. What’s the latest thinking, and how can you profit from it? We give you all the details.
Then we take a close look at glycerol. Does the increased water retention caused by taking this substance really assist performance? If you decide to use it, what factors should you consider, given that higher doses of glycerol have been known to cause headaches and blurred vision?
Hydration at Half-time – what’s the best way to prepare your body for a winning second half?
The half-time nutritional strategies employed by many sports teams typically rely as much on tradition, fashion and even sponsorship deals as they do on sound science – or at least they used to.
With sports like football becoming so high profile, nutritional strategies are increasingly being re-engineered, with many teams employing full-time nutritionists and sport scientists. More and more top teams are using specialist sports drinks and other products with an emphasis on different priorities for different positions and individuals.
The consensus is that the days of sliced oranges and a cup of tea at half-time are long gone. Optimum half-time hydration and refuelling is a complex science in which a number of factors need to be considered. the main factors that need to be considered when formulating the right strategy for the team, allowing for individual differences amongst players. After all, there are significant differences in the physical demands of team sports like soccer, American football and rugby, with soccer being more physically demanding in terms of distance covered per minute than rugby, for instance. Moreover, within the same sport, different league standards are often associated with different activity levels, with top-class sport clearly differentiated from lower levels by the increased volume of high-intensity play.
Given that outcomes in team sports are highly influenced by skill, it is also essential that we consider factors that may influence skill and concentration when considering strategies to optimise performance. Often these factors go hand in hand with carbohydrate depletion, associated with reduced exercise capacity and poor concentration – effects that may be compounded by dehydration.
And as both dehydration and muscle glycogen depletion have been associated with injury and accidents, efforts to prevent these affecting performances could have repercussions well beyond the immediate match.
NB: one of the research studies cited in this chapter points out that the impact of carbohydrate supplementation during the half-time interval could well depend upon the prior eating habits of the player. Similarly, the rehydration needs, and therefore the efficacy of half-time rehydration strategies, will depend on the pre-game hydration status as much as the playing conditions and player work rates.
a report on some recent research from Pennsylvania State University into the effect of dehydration and rehydration on basketball skill. which minerals are essential for half-time nutrition – and which ones may actually be counter-productive.
it’s particularly important to pay attention to player hydration on days when the sun is not shining!
a case study of a prominent UK football club which, having implemented a new pre-match and half-time feeding strategy, found a marked increase in their ability both to score goals in the second half, and to prevent the other side from scoring. The team went on to win the title that year
Hot Weather Hydration - Details of a ‘secret ingredient’ to enhance endurance performance
Endurance athletes competing in hot and humid conditions need to maintain maximum hydration, since fluid losses of as little as 1.5 litres can significantly impair performance. Moreover, studies have shown that many athletes do not drink enough to offset dehydration during competition, even with unlimited access to fluid.
A temporary state of ‘hyper-hydration’ can be achieved by drinking lots of water in excess of the body’s needs. However this situation is very transitory because the consequent fall in osmolarity stimulates the kidneys to remove most of the excess water within an hour, requiring frequent trips to the bathroom, which are not exactly conducive to fast race times!
However there’s a unique molecule which, when added to the water prevents this drop in osmolarity and can prolong the period of hyper-hydration for up to four hours – which explains its use by elite athletes seeking to enhance endurance performance in hot weather conditions. Please note: this is not an artificial chemical. In fact, your body produces it naturally.
you should be aware that there are some possible side-effects when ingesting this substance in greater amounts than the body normally produces. So, to minimise the likelihood of this, our discussion includes full details of an ingestion protocol used in a recent clinical trial that produced significant hyper-hydration without any side-effects.
Diuretics & Hydration – the low-down on caffeine and alcohol
Like it or not, alcohol and caffeine are drugs that most of us consume regularly as part of our diet. And like all drugs, they have side effects, one of which is common to both – a ‘diuretic’ (water-loss) effect.
But how strong is this effect, and is a diet containing these drugs detrimental to the goal of optimum hydration – and sporting success?
the results of some recent research into the consumption of caffeine and alcohol by athletes, specifically their impact on hydration. Should you avoid tea and coffee altogether?
Are caffeine-heavy energy drinks all they’re cracked up to be?
Can athletes drink any alcohol during the sporting season, or is total abstention required?
Sports Drinks – a new breed of carbohydrate drink, promising a genuine improvement in endurance performance
The marketing of sports drinks is a highly-competitive – and lucrative – business for the manufacturers concerned. But for the athlete and coach it can be a confusing subject. Which drinks, if any, offer a real competitive advantage, and which are more hype than substance?
It often seems you’re better off taking many manufacturers’ claims with a large pinch of salt!
Now the indications are that recent sports science research into carbohydrate absorption and utilisation could herald a new breed of carbohydrate drink – one which promises genuinely enhanced endurance performance. carbohydrate during endurance events, and the background to modern carbohydrate drink formulation. recent research on the potential benefits of mixed carbohydrate drinks made using this new formulation, and for endurance athletes..
REGARDS
DR.P.NAGARAJ.PT.,
CONS.PHYSIOTHERAPIST & SPORTS MEDICINE REHABILITATION SPECIALIST
CHENNAI
www.pmnspeciaality.com
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