Single vs Multi-Source Carbohydrate Ingestion During Exercise Written By Science in Sport Team 2 minutesShare The effects of carbohydrate (CHO) ingestion during both endurance and intermittent exercise are well-documented in the scientific literature 1,2,3. It is now common practice for both athletes and individuals engaged in athletic activities/competitions to consume carbohydrates during exercise, usually in the form of carbohydrate drinks and/or gels. Current sports nutrition guidelines recommend the consumption of different CHO intakes based on the duration of exercise, with 30-60g per hour being recommended for exercise lasting between 1-2.5h and up to 90g per hour for exercise lasting over 2.5h 2,3. CHO consumption during exercise is thought to improve performance by maintaining plasma glucose and high CHO oxidation rates (amounts of carbohydrates being used for energy production), sparing glycogen utilisation and by acting directly on the central nervous system 4. The maximal CHO oxidation rates of glucose is of 1.1g.min-1, with the limiting factor being likely represented by the number of intestinal glucose transporters being saturated at this intake5. The provision of additional fructose increases the oxidation rate by up to 50% 6 and can enhance exercise performance 1,2,6. Nevertheless, it must be emphasized that the beneficial effects of additional fructose ingestion only occur when the intestinal glucose transporters are saturated, therefore when consuming carbohydrate at an intake of over 60-70 g/h 1.2 and when exercise is prolonged (i.e. over 2.5-3h) 6. Therefore, for individuals who compete in shorter events (i.e. 1-2h) and consume CHO at an intake of less than 60-70g per hour, it is likely that consuming commercially available glucose-fructose mixtures (drinks or gels), as opposed to glucose only, may reduce plasma glucose availability and therefore lead to reduced CHO oxidation during exercise, negatively impacting exercise performance. Indeed, reduced plasma glucose availability and total CHO oxidation rates were previously identified when participants ingested gels containing a glucose-fructose mix (13g glucose, 7g fructose) at a rate of 60g/h while completing a half-marathon as opposed to an isocaloric glucose only intake 7. In line with the above rationale, current sports nutrition guidelines 3 recommend the consumption of multiple transportable carbohydrates (mixtures of glucose : fructose, e.g. BETA Fuel gels) only during endurance events lasting over 2.5h and when CHO intake reaches up to 90g/h, with single source carbohydrates (glucose, e.g. GO Isotonic Energy gel) being prepared for events lasting less than 2.5h and when CHO intake only reaches up to 60g/h. REFERENCES Stellingwerff, T. and Cox, G.R., 2014. Systematic review: Carbohydrate supplementation on exercise performance or capacity of varying durations. Applied physiology, nutrition, and metabolism, 39(9), pp.998-1011. Jeukendrup, A., 2014. A step towards personalized sports nutrition: carbohydrate intake during exercise. Sports medicine, 44(Suppl 1), pp.25-33. Thomas, D.T., Erdman, K.A. and Burke, L.M., 2016. Position of the Academy of Nutrition and Dietetics, Dietitians of Canada, and the American College of Sports Medicine: nutrition and athletic performance. Journal of the Academy of Nutrition and Dietetics, 116(3), pp.501-528. Rollo, I., Gonzalez, J.T., Fuchs, C.J., van Loon, L.J. and Williams, C., 2020. Primary, secondary, and tertiary effects of carbohydrate ingestion during exercise. Sports Medicine, 50, pp.1863-1871. Jeukendrup, A.E. and Jentjens, R., 2000. Oxidation of carbohydrate feedings during prolonged exercise: current thoughts, guidelines and directions for future research. Sports medicine, 29, pp.407-424. Jeukendrup, A.E., 2010. Carbohydrate and exercise performance: the role of multiple transportable carbohydrates. Current Opinion in Clinical Nutrition & Metabolic Care, 13(4), pp.452-457. Lee, M.J.C., Hammond, K.M., Vasdev, A., Poole, K.L., Impey, S.G., Close, G.L. and Morton, J.P., 2014. Self-selecting fluid intake while maintaining high carbohydrate availability does not impair half-marathon performance. International journal of sports medicine, 35(14), pp.1216-1222. Written By Science in Sport Team Science in Sport Team Supplying world-class knowledge, elite insights, and product recommendations to provide optimal performance solutions for all athletes across a wide variety of endurance sports. More articles by author Shop the article GO Isotonic Energy Gel Pink Grapefruit 30 Pack£40.00Shop Now Beta Fuel Gel - Orange - 30 Pack£66.00Shop Now GO Energy + Electrolyte Gel Salted Caramel - 30 Pack£57.00Shop Now