Drink your sports beverage ice-cold for better times
In warm weather, sports drinks work better if you drink them like those toned models do in TV commercials: ice cold and with condensation dripping off them. In 2006 British sports scientists at the University of Birmingham published the results of a study that provided convincing evidence of the added value of cooled sports drinks.


The researchers did an experiment with 8 healthy young men with an average age of 27. They got the men to cycle twice in a room where the temperature was 34 degrees Celsius.The subjects had to cycle at 65 percent of their VO2max – an exertion level at which they couldn't quite keep up a conversation – and to do so for as long as possible.
The sports drink contained 2 kcal carbohydrates per 100 ml. On one occasion the drink had been cooled to 4 degrees Celsius; on the other occasion the drink was at about room temperature, 19 degrees Celsius. The men had to drink at least 300 ml every 15 minutes. They were allowed to drink more if they wanted, but not less. The researchers had calculated that an intake of 300 ml per 15 minutes would maintain the men's fluid levels.
The figures below show that the men who drank the cooled sports drink cycled for an average of seven minutes longer. Their heartbeat was a little lower, as was their body temperature.

The researchers conclude that cold sports drinks cool down the body, and this effect, even if only modest, means that the body doesn't have to expend so much energy on temperature regulation. And as a result there's more energy available for physical performance.

Exp Physiol. 2006 Sep;91(5):925-33.