From Ergo Log
When it’s hot outside, cold sports drinks work better. Sports scientists at Loughborough University in England showed in 2008 that cold sports drinks boost endurance athletes’ stamina more than lukewarm drinks do.
The researchers did an experiment with eight healthy, moderately active subjects, who were not used to the heat. During the experiments the outside temperature was 4 degrees above freezing, whereas the temperature in the lab was 35 degrees Celsius and the air humidity was 60 percent.
The subjects had to cycle to the point of exhaustion, and every three minutes the researchers got the men to cycle a little faster. Every ten minutes the men were given a beaker containing 100 ml of sugar-free lemonade. On one occasion the temperature of the lemonade was 4 degrees [Cold] – the temperature of an average refrigerator – and on the other occasion the temperature of the lemonade was 37 degrees [Warm].
The subjects managed to cycle for 63.8 minutes when given the cold drink. When given the warm drink they only managed to cycle for 52.0 minutes. The figure below shows why: the cold sports drink reduced the amount that their body temperature rose. The men were less affected by the heat and became less quickly fatigued.
“Unlike conventional precooling maneuvers, often criticized due to their impracticality, an improved endurance capacity with precooling via drinking cold fluids seems attractive”, the researchers conclude, “taking into account that hydration before and during an endurance activity, especially in hot environments, is widely advocated.”
Med Sci Sports Exerc. 2008 Sep; 40(9): 1637-44.