The subjects, all of whom completed an average of 2.5 hours of cycling per week as well as other endurance activities, carried out three 60-minute trials under the following conditions:
1. no fluid at all;
2. 1,200ml of distilled water;
3. 1,200ml of the sports drink Gatorade.
Following a warm-up, the subjects cycled for 60 minutes at their highest possible power output, maintaining 40-80rpm. Heart rate, RPE (rating of perceived exertion) and power output were monitored at regular intervals throughout the trial.
Are you sitting comfortably? Well, this study found that fluid replacement with Gatorade during an hour of moderately intense exercise did not produce any meaningful effects on power output, heart rate, sweat rate, rate of perceived exertion or urine electrolyte concentrations when compared with no fluid ingestion or water alone. In other words, the sports drink didn't work.
Although we shouldn't dismiss all of the previous research suggesting that commercial sports drinks can help improve performance, it may be that they only have a substantial impact during longer-term activities. More research is needed, but this study does raise a valid point: do we need to spend substantial amount of money on sports drinks when plain old water will do?