C.M. Williamson-Reisdorph1, E.E. Bechke2, C. McLester2, B. Buresh2, FASCM, M. L. Millard-Stafford3, FASCM, R. Rooks2, B. Nickerson4, B.M. Kliszczewicz, FASCM2

1 University of Montana, Missoula, MT; 2Kennesaw State University, Kennesaw, GA; 3Georgia Institute of Technology, Atlanta, GA; 4Texas A&M International University, Laredo, TX

Carbohydrate (CHO) rinsing in the mouth (without ingestion) may improve endurance performance purportedly due to alterations in central command following detection of CHO at receptors in the oral cavity. PURPOSE: To examine the effect of CHO rinsing on autonomic and metabolic responses during the post-exercise recovery period to determine if rinsing could enhance post-exercise recovery. METHODS: Ten male recreational cyclists (age = 30 ± 6 years, VO2max= 54.5 ± 8.1 mL·kg-1·min-1) completed experimental trials in a randomized, double-blind, placebo-controlled, crossover design between CHO and placebo (PLA) rinse. The rinse was administered every 12.5% of prescribed work during a 1-hour cycling time trial at 75% Wmax. Heart rate variability (lnRMSSD), respiratory exchange ratio, and blood sampling for epinephrine, norepinephrine, insulin, glucose, free fatty acids, and lactate were completed pre- and post- exercise. RESULTS: CHO rinsing did not result in improvements in time trial performance (p = 0.545). A prolonged elevation of sympathetic nervous system (SNS) activity was observed at 30-minutes post-exercise in the CHO trial, as measured by lnRMSSD and epinephrine (p = 0.046, p = 0.022). Lactate remained elevated at 30-minutes post-exercise in the CHO rinse trial (p < 0.001). A significant interaction was observed with higher free fatty acid concentrations occurring post-exercise in CHO trial (p = 0.024). A reduction in blood glucose concentrations occurred in the PLA trial (p = 0.021), but not in the CHO trial (p = 0.657). CONCLUSION: Periodic CHO mouth rinsing had no impact on 1-hour time trial performance in recreational cyclists. CHO rinsing resulted in prolonged elevation of SNS activity for up to 30-minutes post-exercise and altered metabolic activity as measured by epinephrine, free fatty acids, glucose, and lactate. Therefore, the use of a CHO rinse does not enhance post-exercise recovery.

Supported by the Department of Exercise Science & Sport Management at Kennesaw State University.

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