Too, B. W., Cicai, S., Hockett, K. R., Applegate, E., Davis, B. A., & Casazza, G. A. (2012). Effect of a natural versus commercial product on running performance and gastrointestinal tolerance. Presentation 2361 at the 59th Annual Meeting of the American College of Sports Medicine, San Francisco, California; May 29-June 2, 2012.

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This study examined the effects of raisins and chews on running performance and gastrointestinal tolerance in male runners (N = 11). Ss completed three randomized trials (raisins, chews, and water-only) with seven days between each trial. A trial consisted of 80-minutes of submaximal (75%VO2max) running followed by a 5-km time-trial. Heart rate, respiratory exchange ratio, glucose, lactate, free fatty acids, glycerol, insulin, electrolytes, creatine kinase, gastrointestinal symptoms, and rating of perceived exertion were recorded every twenty minutes during the submaximal trial and at the end of the time-trial. Whole body muscle soreness and fatigue were also measured.

Oxygen uptake, heart rate, muscle soreness and fatigue, electrolytes, lactate, and ratings of perceived exertion did not differ between treatments. Respiratory exchange ratio was significantly higher during the two carbohydrate treatments, as was blood glucose. Plasma creatine kinase was higher with raisins. Time to complete the time-trial was shorter for both carbohydrate treatments. Gastrointestinal disturbance was mild for all treatments.

Implication. The carbohydrate variants of raisins and chews maintained high blood glucose levels and improved running performance compared to a water-only treatment. Running performance between the raisins and chews were similar with no significant gastrointestinal differences.

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