M. Pearson, E. McMorris, D. Creek, B. Dixon, and W. M. Silvers

Whitworth University, Spokane, WA

Much research has documented the importance of carbohydrate ingestion (CHO) during endurance exercise to prolong fatigue and enhance performance. However, little research has examined the effects of CHO mouth rinse as an alternative to CHO ingestion. PURPOSE: The purpose of this study was to compare the effects of a CHO mouth rinse and a placebo on: 1) respiratory exchange ratio (RER), 2) rating of perceived exertion (RPE), 3) heart rate (HR), and 4) blood glucose levels during endurance running. METHODS: Seven recreationally trained participants (nm=6, nf=1) aged 22-45 yrs. old volunteered for the study. All participants first underwent a familiarization trial on the treadmill to determine VO2max and corresponding speeds for 70% VO2max. In two separate testing sessions, participants received either a CHO or placebo solution, in a random order and double blind fashion. The CHO rinse was a 6.4% maltodextrin solution and the placebo was plain water. For each testing session, participants ran at 70% VO2max for 45-95 minutes in an attempt to elicit a fatigue-inducing running scenario. During the run, participants rinsed 25 mL of solution in their mouths for 5 sec every 5 min. RPE was recorded every 10 min, blood glucose every 15 min, and HR and VO2 were continuously measured throughout the testing session. RESULTS: A Wilcoxon Signed Rank Test indicated that there were no statistical differences in RER (p = 0.24), RPE (p = 0.61), HR (p = 0.87), or blood glucose (p = 0.39) between solutions. CONCLUSIONS: For this present study, the CHO mouth rinse had no beneficial effects for any measured dependent variable during endurance running. These findings were most likely due to: 1) an intensity of 70% of VO2max was not high enough to utilize CHO as a major fuel source during the exercise bout, 2) full fatigue may not have been reached without a time-to-exhaustion performance, or 3) the CHO mouth rinse may not have been concentrated enough. Future research should sample a greater number of participants using a time-to-exhaustion or long distance time trial to elicit results with higher statistical power and improved application to real-world running performance.

This document is currently not available here.