In contrast, consuming low-glycemic CHO rich foods (starch with high amylose Mdivi1 mouse content or moderate glycemic CHO with high dietary fiber content) in the immediate 45-60 minute pre-exercise period allows for slower glucose absorption, reducing the potential for rebound glycemic response. Typically, the optimal forms of CHO have been combinations of glucose, fructose, sucrose, and maltodextrins with or without

protein or amino acids and it has been further suggested that the glycemic index of food may be a key determining factor for when food is ingested relative to exercise participation [11–18]. Gastric emptying also affects fluid hydration and S63845 manufacturer absorption of nutrients. Gastric emptying slows when ingested fluids contain a high concentration of particle in solution (osmolality) or possess high caloric content. The rate the stomach empties greatly affects intestinal absorption of fluid and nutrients. Little negative effect of exercise on gastric emptying occurs up to an check details intensity of about 75% of maximum, after which emptying rate slows [19]. Gastric volume, however, greatly influences gastric emptying; the emptying rate increases exponentially as fluid volume in the stomach increases. A major factor to speed

gastric emptying (and compensate for any inhibitory effects of the beverage’s carbohydrate content) involves keeping a relatively high fluid volume in the stomach. Consuming 150-250 ml of fluid immediately before exercise optimizes the beneficial effect of increased stomach

volume on fluid and nutrient passage into the intestine. Prior research has also indicated that colder fluid emptied from the stomach at a faster rate than fluid at room temperature [3]. As a general rule, a 5 to 8% CHO-electrolyte beverage consumed during exercise in the heat contributes to temperature regulation and fluid balance as effectively as plain water by providing an intestinal energy delivery rate of approximately 5.0 kilocalories the per minute in helping maintain glucose metabolism and glycogen reserves in prolonged exercise [20, 21]. Another factor influencing absorption is the consumption of triglycerides composed of predominantly long-chain fatty acids (12-18 carbons) significantly delays gastric emptying. This affects the rapidity of fat availability negatively and also slows fluid and CHO replenishment, both crucial factors in high intensity endurance exercise. Consequently, the relatively slow rate of gastric emptying and subsequent digestion, absorption, and assimilation of long-chain triglycerides makes this energy source an undesirable supplement to augment energy metabolism [22]. Medium-chain triglycerides (MCTs) on the other hand provide a more rapid source of fatty acid fuel. MCTs are processed oils frequently produced for patients with intestinal malabsorption and tissue wasting diseases.