According to a new study published in the American Journal of Physiology – Endocrinology & Metabolism by researchers from the University of Bath in the United Kingdom, consuming basic table sugar with water during long-distance endurance training or competition could be the difference between a successful run (cycle, swim, etc.) and prematurely “hitting the wall.” The team assessed the impact of consuming specific carbohydrate beverages during endurance exercise on liver glycogen depletion to determine what types may best help thwart fatigue. They assessed various sucrose- and glucose-based drinks using long-distance cyclists. The data showed that ingesting either glucose or sucrose (table sugar) prevents the regular decline in liver carbohydrate stores and can help avert rapid central fatigue; but sucrose may have distinct advantages.
Although an increasing number of sport performance drinks now include sucrose, or mixtures of glucose and fructose; many still rely on glucose alone. Sucrose molecules are comprised of one fructose and one glucose molecule linked together. Interestingly, it appears that combining different sugar sources in a sport beverage can help improve the rate of fluid and carbohydrate absorption in the gut - consequently reducing discomfort while providing energy more effectively. Lead researcher Dr. Javier Gonzalez explained, “The carbohydrate stores in our liver are vitally important when it comes to endurance exercise as they help us to maintain a stable blood sugar level. However, whilst we have a relatively good understanding of the changes in our muscle carbohydrate stores with exercise and nutrition, we know very little about optimizing liver carbohydrate stores during and after exercise.” He went on to explain that the cyclists participating in the study who consumed a table sugar-based beverage experienced improved performance as well as superior gut comfort when compared with those who consumed glucose-only fluids.
The research team summarized their findings by recommending that endurance enthusiasts consume beverages containing up to 90 grams of sugar per hour (diluted to 8 grams per 100 ml of fluid) that combine multiple simple sugar sources. Following the aforementioned guidelines will help individuals achieve optimal performance during exercise lasting longer than 2.5 hours.