Purpose: The aim of this study was to investigate the influence of mouth rinsing a CHO-electrolyte (CHO-E) solution on 1-h running performance. A second study determined whether mouth rinsing a CHO-E solution altered the blood glucose and plasma insulin concentrations at rest.
Methods: After a 13-h fast, 10 endurance-trained male runners completed two 1-h performance runs on an automated treadmill while mouth rinsing 25 mL of either a 6.4% CHO-E (C) or placebo (P) solution immediately before and at 15-min intervals during the 1-h run. An additional 10 healthy active males followed the same mouth rinsing procedure during a 1-h resting period. Finger prick blood samples were obtained for the determination of blood glucose and plasma insulin concentrations.
Results: Runners covered 211 m (90% confidence intervals = 42-380 m, P = 0.048) further during the C trial (14,298 ± 685 m, mean ± SD) in comparison with the P trial (14,086 ± 732 m). There was no change in blood glucose concentrations during the 1-h run (P: pre = 4.3 ± 0.2 mmol·L(-1), post = 4.3 ± 0.3 mmol·L(-1); C: pre = 4.3 ± 0.4 mmol·L(-1), post = 4.3 ± 0.3 mmol·L(-1)). At rest, there was no change in blood glucose (P: 4.3 ± 0.1 mmol·L(-1), C: 4.3 ± 0.2 mmol·L(-1)) or plasma insulin (P: 6.2 ± 1.1 mU·L(-1), CHO: 5.9 ± 1.0 1.1 mU·L(-1)) concentrations (P > 0.10).
Conclusions: Mouth rinsing a 6.4% CHO-E solution was associated with increased distance covered during a 1-h performance run in comparison to mouth rinsing a placebo solution. Mouth rinsing a CHO-E was not associated with changes in blood glucose concentration during exercise or at rest.