Fueling a ride is essential to avoid the bonk, the dreaded energy crash, but there’s a limit to how much carbohydrates the body is able to absorb. How much carbs is enough?
Scientists in the Department of Sports Studies at the University of Stirling measured the performance of cyclists drinking either water or one of three sports drinks containing 20, 39 or 64g carbohydrate in a series of tests.
The cyclists, each of whom have trained for more than six hours a week for more than three years had to ride for two hours at 95% of their lactate threshold, and then do a 30-minute time trial at 70% of their peak power output.
Drinking 20g of carbs an hour saw no obvious gain over water, but both the higher-carb drinks resulted in significantly faster time trials, reducing the time by 6.1% (39g an hour) and 6.5% (64g an hour).
The cyclists drinking sports drinks containing 39 and 64g of carbohydrate were similarly effective at improving endurance cycling performance in comparison to a 0g/hour control in our trained cyclists.