Fuelling a ride is vital to avoid the bonk, the dreaded energy crash, but there’s a limit to how much carbohydrate the body can absorb.
Scientists in the Department of Sports Studies at the University of Stirling measured the impact of cyclists consuming either water, or one of three sports drinks containing 20, 39 or 64g carbohydrate in a series of tests.
The riders, each of whom have trained for more than six hours per week for more than three years had to ride for two hours at 95% of their lactate threshold, and then undertake a 30-minute time trial at 70% of their peak power output.
Drinking 20g of carbs per hour delivered no appreciable gain over water, but both the higher-carb drinks led to significantly faster time trials, reducing the time by 6.1% (39g per hour) and 6.5% (64g per hour).
Consuming 39 and 64g per hour of carbohydrate, “…were similarly effective at improving endurance cycling performance compared with a 0g/hour control in our trained cyclists…” report the researchers in the International Journal of Sport Nutrition and Exercise Metabolism.