Sorry, couldn't help myself. From the AID website:
http://www.ausport.gov.au/ais/nutrition/factsheets/hydration/fluid_-_who_needs_it
What should athletes drink?
Research shows that fluid intake is enhanced when beverages are cool (~15 °C), flavoured and contain sodium (salt). This makes sports drinks an ideal choice during exercise. Sports drinks are not gimmicks. They are legitimate products that are well researched and proven to improve fluid intake and performance. A great deal of science has gone into developing the flavour profile of sports drinks so that they encourage fluid intake during exercise. In addition, sports drinks contain carbohydrate at a concentration (4-8%) that allows refueling to take place during exercise.
Several studies demonstrate that use of sports drinks will improve fluid intake. A study conducted with AIS netball and basketball players in 1999 demonstrated better fluid balance with a sports drink compared to water. This is consistently observed across our sporting programs. Even athletes who prefer to drink water during exercise, demonstrate better fluid intake when forced to drink sports drink.
In the past, it was believed that sports drinks only benefited the performance of exercise greater than 90 minutes. However, in recent years, the intake of carbohydrate and fluid has been shown to be beneficial for high intensity exercise of approximately 60 minutes. This makes sports drinks a good option for many types of sporting activity.
Water is still a suitable option during exercise. However, water drinkers need to be aware that water does not stimulate fluid intake to the same extent as sports drinks. Drinking to a plan is therefore crucial when drinking water. Don't rely on thirst.
Cordial, soft drinks and juice generally contain greater than 10% carbohydrate and are low in sodium. This can slow down gastric emptying and makes these drinks a less suitable choice, especially for high intensity activity. Some athletes, exercising at low intensities may tolerate juice, soft drink and cordial but in most situations, sports drinks are the better option.
Which sports drink is the best?
Food standards in Australia place restrictions on the formulation of sports drinks. As a result, sports drinks sold in Australia are very similar in composition (see the table below). Choose sports drinks that have 4-8% carbohydrate, 10-20 mmol/L sodium, are affordable, come in a convenient package and taste good.
[table doesn't copy/paste]
Is it possible to drink too much?
Consuming fluid in excess of requirements may cause some gastrointestinal discomfort. In extreme cases, a condition called hyponatraemia can occur. Hyponatraemia (low blood sodium levels) causes symptoms similar to dehydration and is potentially life threatening. It is not common but can occur in prolonged endurance events (> 2 hours) when large volumes of low sodium drinks (such as water) are consumed and sweat losses are small. Those most at risk are small females who have long race times. This group of athletes tends to have small sweat losses and plenty of time to consume large amounts of fluid during the event. Consuming sodium-containing fluids such as sports drink and matching fluid intake to sweat loss lowers the risk of hyponatraemia.
Sports drinks and dental health
Sports drinks, like other carbohydrate containing fluids, including soft drinks and fruit juices, have been shown to contribute to dental erosion. To help reduce the potential impact of sports drinks on dental health, athletes should:
Minimise the contact time the sports drink has with their teeth. Do not hold or swish sports drinks in your mouth. A straw or squeezy bottle can also minimise contact time with the teeth by directing fluids towards the back of the mouth.
Where practical, consume dairy products or chew sugar free gum immediately after consumption of the sports drink.
Avoid brushing teeth for at least 30 minutes after consuming sports drink to allow tooth enamel to re-harden.
