Carbohydrate Mouth Rinsing Has No Effect on Power Output During Cycling in a Glycogen-reduced State
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Ali, A
Yoo, M
Moss, C
Breier, B
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BioMed Central
Abstract
Background: The effect of mouth rinsing with a carbohydrate (CHO) solution on exercise performance is inconclusive
with no benefits observed in the fed state. This study examined the effect of CHO mouth rinse or CHO ingestion on
performance in 9 moderately trained male cyclists.
Methods: Four trials were undertaken, separated by 7 days, in a randomized, counterbalanced design. Each trial
included a 90-min glycogen-reducing exercise protocol, immediately followed by a low CHO meal and subsequent
overnight fast; the following morning a 1-h cycling time trial was conducted. The trials included 15 % CHO mouth
rinse (CHOR), 7.5 % CHO ingestion (CHOI), placebo mouth rinse and placebo ingestion. Solutions were provided after
every 12.5 % of completed exercise: 1.5 mL · kg−1 and 0.33 mL · kg−1 body mass during ingestion and rinse trials,
respectively. During rinse trials participants swirled the solution for 8 s before expectorating. Blood samples were taken
at regular intervals before and during exercise.
Results: Performance time was not different between trials (P = 0.21) but the 4.5-5.2 % difference between CHOI and
other trials showed moderate practical significance (Cohen’s d 0.57-0.65). Power output was higher in CHOI relative to
other trials (P < 0.01). There were no differences between CHOR and placebo groups for any performance variables.
Plasma glucose, insulin and lactate concentrations were higher in CHOI relative to other groups (P < 0.05).
Conclusions: In a fasted and glycogen-reduced state ingestion of a CHO solution during high-intensity exercise
enhanced performance through stimulation of insulin-mediated glucose uptake. The CHO mouth rinsing had neither
ergogenic effects nor changes in endocrine or metabolic responses relative to placebo.
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Keywords
Ergogenic aid; Fluid ingestion; Time trial; Sports drink; Mouthwash; Supplementation
Source
Journal of the International Society of Sports Nutrition, 13(1), 19.
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© 2016 Ali et al. Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International
License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any
medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative
Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://
creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.