Can carbohydrate mouth rinse improve performance during exercise? A systematic review.
The purpose of this review was to identify studies that have investigated the effect of carbohydrate (CHO) mouth rinse on exercise performance, and to quantify the overall mean difference of this type of manipulation across the studies. The main mechanisms involving the potential benefit of CHO mouth rinse on performance was also explored. A systematic review was conducted in the following electronic databases: PubMed, SciELO, Science Direct, MEDLINE, and the Cochrane Library (Cochrane Central Register of Controlled Trials), without limit of searches. Eleven studies were classified as appropriate and their results were summarized and compared. In nine of them, CHO mouth rinse increased the performance (range from 1.50% to 11.59%) during moderate- to high-intensity exercise (~75% Wmax or 65% VO2max, ~1 h duration). A statistical analysis to quantify the individual and overall mean differences was performed in seven of the 11 eligible studies that reported power output (watts, W) as the main performance outcome. The overall mean difference was calculated using a random-effect model that accounts for true variation in effects occurring in each study, as well as random error within a single study. The overall effect of CHO mouth rinse on performance was significant (mean difference=5.05 W, 95% CI 0.90 to 9.2 W, z=2.39, p=0.02) but there was a large heterogeneity between the studies (I2=52%). An activation of the oral receptors and consequently brain areas involved with reward (insula/operculum frontal, orbitofrontal cortex, and striatum) is suggested as a possible physiological mechanism responsible for the improved performance with CHO mouth rinse. However, this positive effect seems to be accentuated when muscle and liver glycogen stores are reduced, possibly due to a greater sensitivity of the oral receptors, and require further investigation. Differences in duration of fasting before the trial, duration of mouth rinse, type of activity, exercise protocols, and sample size may account for the large variability between the studies.
Sport Science Research Group, Department of Physical Education and Sports Science (CAV), Federal University of Pernambuco, Alto do Reservatório street, Bela Vista, Vitória de Santo Antão, Pernambuco 55608-680, Brazil. carolleandro22@gmail.com.
Thays
T
de Ataide e Silva
Sport Science Research Group, Department of Physical Education and Sports Science (CAV), Federal University of Pernambuco, Alto do Reservatório street, Bela Vista, Vitória de Santo Antão, Pernambuco 55608-680, Brazil. dicavalcanti@hotmail.com.br.
Maria Eduarda
ME
Di Cavalcanti Alves de Souza
Sport Science Research Group, Department of Physical Education and Sports Science (CAV), Federal University of Pernambuco, Alto do Reservatório street, Bela Vista, Vitória de Santo Antão, Pernambuco 55608-680, Brazil. jamiferro@hotmail.com.
Jamile Ferro
JF
de Amorim
College of Health and Biomedicine and Institute of Sport Exercise and Active Living (iSEAL), Victoria University, Melbourne 8001, Australia. christos.stathis@vu.edu.au.
Christos G
CG
Stathis
Laboratory of Physiology and Pharmacology, Department of Physical Education and Sports Science (CAV), Federal University of Pernambuco, Alto do Reservatório street, Bela Vista, Vitória de Santo Antão, Pernambuco 55608-680, Brazil. carolleandro22@gmail.com.
Carol Góis
CG
Leandro
Sport Science Research Group, Department of Physical Education and Sports Science (CAV), Federal University of Pernambuco, Alto do Reservatório street, Bela Vista, Vitória de Santo Antão, Pernambuco 55608-680, Brazil. adrianosilva@usp.br.
Adriano Eduardo
AE
Lima-Silva
D015444:Exercise / Q000502:physiology*; D005947:Glucose / Q000008:administration & dosage*; D006801:Humans; D009055:Mouth / Q000502:physiology*; D010807:Physical Endurance / Q000187:drug effects / Q000502:physiology; D011134:Polysaccharides / Q000008:administration & dosage*; D016032:Randomized Controlled Trials as Topic
D011134:Polysaccharides; C008315:maltodextrin; D005947:Glucose