What Sports Drinks Do
Sports drinks contain carbohydrates and electrolytes to replace lost body salt and to replenish muscle energy stores. For endurance activities such as walking, running, or cycling, the body burns through its available muscle energy stores in the first 45 minutes. A sports drink does several things - it replaces the water, sodium and potassium lost in sweat and it provides carbohydrates for ready energy so the muscles can continue to perform.Carbs Plus Protein No Better for Endurance
In the study, a sports drink that has a 4:1 carbohydrate to protein ratio was compared to standard Gatorade-type sports drink and to a placebo drink that tasted similar but had neither carbohydrates nor protein. Cyclists did not know which beverage they were given during any session. They rode an 80 kilometer time trial, drinking every 15 minutes. Then 7 days later they did it again with one of the other samples, and again 7 days later with the third. Their time trial times were 4.4% faster with either the carbohydrate-only sport drink (such as Gatorade) or the carbohydrate and protein drink (such as Accelerade) over their times with the placebo drink.Why the Difference Between Studies?
Why did this study find no difference while the previous study did? The authors say that in the previous study, the subjects were drinking less than is considered best for performance. The previous study also didn't mimic real-world race conditions, as the new study did, but instead exercised the cyclists to fatigue. The new study was funded by Gatorade as they decided whether to market a protein-added sports drink.What Should You Drink?
The International Marathon Medical Director's Association revised guidelines for drinking and fluid intake for walkers and runners at endurance events in May 2006. For a workout of 30 minutes or more, they recommend drinking sports drink, and not diluting it or alternating sports drink with water. The carbohydrate and electrolytes in the sports drink helps the body absorb water faster, and provides energy for the body. If you dilute the sports drink, you decrease the benefits.Drinking Guidelines 2006
Sources
VAN ESSEN, MARTIN; GIBALA, MARTIN J. "Failure of Protein to Improve Time Trial Performance when Added to a Sports Drink" Medicine & Science in Sports & Exercise, August 2006, 38:8.SAUNDERS, MICHAEL J.; KANE, MARK D.; TODD, M. KENT. "Effects of a Carbohydrate-Protein Beverage on Cycling Endurance and Muscle Damage." Medicine & Science in Sports & Exercise, July 2004, 36:7.
Lewis G. Maharam, MD.FACSM (chair),Tamara Hew DPM, Arthur Siegel MD, Marv Adner, MD, Bruce Adams, MD and Pedro Pujol, MD, FACSM. "IMMDA’s Revised Fluid Recommendations for Runners and Walkers." IMMDA. 6 May 2006.
