Sodas with HFCS and Caffeine May Be Best Drinks for Endurance

The limiting factor in endurance racing is the time that it takes to get enough oxygen into muscles to burn food for energy. Anything that reduces oxygen requirements allows you to race faster. Sugar stored in muscles, called glycogen, requires less oxygen than fat or protein. Anything that helps you keep sugar in muscles longer gives you greater endurance.
 
A study from Georgia State University shows that drinks that contain both glucose and fructose burn more carbohydrates than those containing only glucose, and allow cyclists to ride much faster over 60 miles (International Journal of Sport Nutrition and Exercise Metabolism, April 2010).
 
Most soft drinks are sweetened with high fructose corn syrup (HFCS). Both HFCS and conventional sugar (sucrose) contain a mixture of two sugars, glucose and fructose, in nearly the same concentrations: HFCS has 55 percent fructose/42 percent glucose, while sucrose is a 50/50 mixture. So the relative concentrations of glucose and fructose are not significant. However, the fructose in sucrose from cane or beet sugar is bound to glucose and must first be separated from it, so it is absorbed more slowly into the bloodstream. The manufacturing process for HFCS frees the fructose from glucose to makes it into a free, unbound form that is absorbed more rapidly into the bloodstream. This could cause a higher rise in blood sugar ((Pharmacology, Biochemistry and Behavior, March 18, 2010) and provide more sugar for muscles during exercise.  We need to wait for more research to know if HFCS drinks improve endurance more those made with cane or beet sugar.
 
Caffeine increases endurance (Medicine & Science in Sports & Exercise, July 2010) by increasing absorption of sugar by muscles (Journal of Applied Physiology, June 2006). Those who took sugared drinks with caffeine were able to absorb and use 26 percent more of the ingested sugar than those who took the same drinks without caffeine.
 
On long rides, we drink colas for their sugar and caffeine. However, you should take sugared drinks only when you exercise and for up to an hour after you finish.  Contracting muscles remove sugar from the bloodstream rapidly without needing much insulin. Taking sugared drinks when you are not exercising causes higher rises in blood sugar that increase risk for diabetes and cell damage.

Photo: flickr//thedabble 

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About dr.gabe.mirkin

A practicing physician for more than 40 years and a radio talk show host for 25, Dr. Mirkin is a graduate of Harvard University and Baylor University College of Medicine. He is one of a very few doctors board-certified in four specialties: Sports Medicine, Allergy and Immunology, Pediatrics and Pediatric Immunology.

Dr. Mirkin's latest book is The Healthy Heart Miracle, published by HarperCollins. He wrote the chapter on sports injuries for the Merck Manual (both lay and physicians' editions), the largest selling book worldwide with over one million copies in print. His daily short features on fitness have been heard on CBS Radio News stations since the 1970's. He has written 16 books including The Sportsmedicine Book, the best-selling book on the subject that has been translated into many languages. More books

Dr. Mirkin did his residency at the Massachusetts General Hospital and over the years he has served as a Teaching Fellow at Johns Hopkins Medical School, Assistant Professor at the University of Maryland, and Associate Clinical Professor in Pediatrics at the Georgetown University School of Medicine.

Dr. Mirkin has run more than forty marathons and is now a serious tandem bike rider with his wife, Diana, often doing 30-60 miles in an outing.

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One Response to Sodas with HFCS and Caffeine May Be Best Drinks for Endurance

  1. LordAragorn22 August 9, 2010 at 3:07 am #

    What a awesome 6 hour, thankyou to Dave and all the crew at Roudtuit Caravan park for all the work that went to running this event, well worth marking in the dairy for next year

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