Download Sports Drinks Factsheet - Lisburn City Swimming Club

Factsheet
Sports Drinks
Introduction
Consuming fluid before and during any form of exercise lasting longer than about 40 min may help to
optimise exercise performance. The consumption of a sports drink can assist with optimizing performance. Sports drinks contain carbohydrate and electrolytes (sodium and potassium) to fuel the body for
exercise and maintain adequate hydration levels and may be better than drinking plain water.
Sports drinks have been designed to ensure quick emptying from the stomach and rapid absorption
from the small intestine. This can help you ingest adequate amounts of liquid to replace fluid lost
through sweat while also providing a carbohydrate energy source.
What are sports drinks?
Sports drinks are carbohydrate-rich fluids that typically contain about 4-8% carbohydrate along with
varying amounts of sodium and potassium. Carbohydrate consumption provides fuel for energy production, and when consumed during exercise can assist with maintaining blood glucose levels. Six-eight
grams of carbohydrate per 100ml appears to be the optimum amount to ensure a quick uptake of carbohydrate into the blood stream. Excessive amounts of carbohydrate (>10g per 100g) can impede gastric emptying, and may increase the risk of gastrointestinal disturbance and therefore impede performance.
Sodium and potassium are added in small amounts to replace losses due to sweating and to conserve
fluid in the muscle cells. The sodium (usually 10-25mmol/L) found in sports drinks assists with fluid retention and also drives our thirst mechanism.
Other ingredients such as potassium, caffeine, amino acids, protein, antioxidant and magnesium have
been added to sports drinks and marketed to further enhance performance. Based on scientific research, the majority of these additional ingredients do not provide any extra performance benefit when
compared to the plain carbohydrate/electrolyte containing sports drink.
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Practical guidelines for use of sports drinks
When to use sports drinks
Before Exercise
Sports drinks may be appropriate for consumption before sporting events to top up carbohydrate
stores and optimise hydration status.
During Exercise
Performance benefits can be seen when sports drinks are consumed during endurance events lasting
longer than 60 minutes.
After Exercise
Sports drink consumption after exercise as part of your nutritional recovery routine can assist with replacing fluid lost through sweat and also carbohydrate stores which will have decreased during exercise.
Proposed volumes of sport drink when exercising
Before Exercise
Consuming beverages in an amount equivalent to 5-7 mL.kg-1 of body weight at least 4 hours before
exercise is ideal. If your urine is dark or you do not produce any urine (i.e. go to the toilet) in the 2
hours before exercise, consumption of an additional 3-5 mL.kg-1 of body weight should be considered.
Fluid consumed before an event can be water or a sports drink. If you are dehydrated, a sports drink
may be favourable.
During Exercise
The goal during exercise is to prevent excessive dehydration, i.e. a weight loss of no more than 2% of
your pre-exercise weight should be the target in most exercise situations.
Fluid loss is unique to each athlete therefore it is difficult to recommend specific fluid and electrolyte
replacement guidelines. Factors such as the type of event, duration, clothing, weather and other factors such as heat acclimatization all play a major role in fluid loss, but even when these are constant,
there is a very large variability between individuals in the sweating response. To assess your personal
fluid loss, weighing before and after a training session or competition can help determine the amount
of fluid you have lost, and therefore assist you regarding the volume of fluid you need to be consuming.
Current recommendations in regards to carbohydrate consumption during endurance exercise longer
than 60 min is 30-60g per hour. This would equate to 0.5-1L of sports drink per hour if no other carbohydrate supplements are being consumed.
After Exercise
To rapidly restore normal hydration status when an athlete is dehydrated, consuming 1.5L of fluid per
1kg of body weight loss is recommended.
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Other considerations when using sports drinks
Sports drinks can easily be ingested whilst running or cycling, though availability can be a problem in
some events when fluid requirements are high. Forward planning is essential.
During ultra endurance racing a variety of flavours can be used to avoid flavour fatigue.
Athletes should trial sports drinks as there are many different formulations and flavours available.
Sports drinks provide an all-in-one option for water, carbohydrate and electrolyte replacement during
exercise.
Concerns about sports drink use
Inappropriate consumption, especially over consumption, may lead to substantial weight gain during
an event (i.e. if fluid intake exceeds fluid loss).
For athletes who are required to meet weight or remain lean, consumption of sports drinks may cause
problems with energy balance (i.e. over consumption of calories).
Consuming large volumes of sports drink in a short period of time, or not consuming enough fluid during exercise, can lead to gastrointestinal disturbances.
Sports drinks, like fruit juice, soft drinks, and other drinks contain sugar. They are also mildly acidic. If
you consume large volumes of sports drinks extra care with dental hygiene should be considered to
prevent tooth decay and enamel erosion.
Summary
Consuming fluid before and during and after exercise help to optimise exercise performance.
Sports drinks contain carbohydrate and electrolytes to fuel the body for exercise and maintain adequate hydration levels.
Inappropriate consumption of sports drinks may be detrimental to performance.
Possible contamination
With any nutritional supplement there is always the risk of contamination in the manufacturing process, which could lead to a supplement containing substances that are not listed on the label.
Athletes are advised to check that any supplement they choose to take has been tested for containing
any banned substances.
The legal clause ‘strict liability’ means that an athlete is responsible for any and all substances that may
appear in his or her urine or blood in a doping test.
It is always advisable to seek professional advice from a Sports Dietitian/Nutritionist regarding any nutrition supplement.
Developed by INDI/SNIG for the Irish Sports Council, 2009
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