Glucose-Fructose Sports Drink More Effective than Glucose-Only Sports Drink
Past research has established that athletes are able to oxidize carbohydrate ingested in a sports drink at a higher rate when the sports drink contains multiple sugars, because different types of sugar are absorbed and metabolized through different pathways. Now, researchers from the University of Birminghman, England, have shown that a multiple-sugar sports drink enhances performance in a race-like endurance effort more than a single-sugar sports drink.
On three occasions, eight cyclists completed a two-hour glycogen depletion ride on a stationary bike followed immediately by a simulated time trial that took roughly one hour to complete. In one trial, subjects consumed plain water. In a second trial, they consumed a glucose-only sports drink, and in a third trial, they consumed a glucose-fructose sports drink containing the same total concentration of carbohydrate as the other sports drink. On average, the subjects completed the glucose-fructose time trial 8 percent faster than the glucose-only trial and 19 percent faster than the water trial. The study's authors also found that total carbohydrate oxidation was equal in the glucose-only and glucose-fructose trials, indicating that exogenous carbohydrate oxidation and glycogen sparing were greater in the glucose-fructose trial--a conclusion they were able to draw based on the previous research alluded to above.
While interesting, this study is unlikely to have any real-world effects, because nearly every sports drink in existence contains multiple sugars. In fact, we can think of only one glucose-only commercial sports drink--called Gleukos--whose makers are probably now wishing they had read the scientific literature on sports drinks before they created theirs. |
