Abstract
PURPOSE: To examine the effects of raisins and chews on running performance and gastrointestinal (GI) tolerance. METHOD: Eleven male (29.3 + or - 2.4 yrs) runners completed three randomized trials (raisins, chews and water only) separated by 7 days apart. Each trial consisted of 80-min submaximal (75%VO2max) running followed by a 5-km time trial (TT). Heart rate (HR), respiratory exchange ratio (RER), glucose, lactate, free fatty acids, glycerol, insulin, electrolytes, creatine kinase, GI symptoms and rating of perceived exertion (RPE) were recorded every 20-min during the submaximal trial and at the end of the TT. Whole body muscle soreness and fatigue were also measured. RESULTS: VO2, HR, muscle soreness and fatigue, electrolytes, lactate and RPE did not differ due to treatment. RER was significantly higher during the carbohydrate treatments, as was blood glucose (104.9 + or - 3.6, 107.0 + or - 2.5, 98.0 + or - 2.9 mg times dl-1 for raisin, chews and water respectively). Plasma creatine kinase was higher with raisins (466.6 + or - 101.7, 308.2 + or - 58.5, 321.5 + or - 48.3 U times L-1 for raisin, chews and water respectively). Time to complete the TT was shorter for both carbohydrate treatments (20.6 + or - 0.8, 20.7 + or - 0.8, 21.6 + or - 0.8 min for raisin, chews and water respectively). GI disturbance was mild for all treatments. CONCLUSION: Both the raisins and chews maintained high blood glucose levels and improved running performance compared to water only. Running performance between the raisins and chews were similar with no significant GI differences.