Carbohydrate mouth rinse fails to improve performance in short distance cycling time trial, study finds

Experienced cyclists who used a CMR prior to a 4 km time trial (TT4km), showed no improvement in completion time compared with placebo, found the research team led by the University of São Paulo.

The pre-race 25 ml dose of CMR, which was spat out rather than ingested, did however reduce the cyclists’ global fatigue and rating of perceived exertion (RPE).

Anecdotal data have suggested the use of CMR to improve exercise performance in real training sessions and competitions, even in short, high intensity cycling, explained the researchers.

“However, the CMR strategy appeared to have no effect on TT4km performance, although global fatigue had been attenuated. Therefore, the present results challenge the use of CMR as a potential ergogenic aid for short, high intensity exercises,”​ wrote lead author Professor Flávio Pires.

Dietary control​

The cyclists were prepared individualised diets (with similar macronutrient composition) by qualified nutritionists for the day before the trial. The participants fasted overnight, and subsequently consumed a standard breakfast two hours prior to the trial.

The cyclists therefore undertook the trial in a ‘fed’ state.  Previous trials using CMRs have shown inconsistent results, noted the scientists.  Some have shown performance benefits in both fed and fasting states, some showed no improvement in a fed state, while others showed enhanced performance only in a fasted state.

Study limitations​

As the time trial was conducted under laboratory conditions, using a simulator attached to the participants’ own bikes, the scientists suggested that replicating results in real-life settings would be helpful.

The reduction in global fatigue might provide an edge under such conditions, they hypothesised.  

“Further tests should be performed to verify if these likely differences in global fatigue might represent an edge in training sessions combining multiple exercise bouts, or in the end-spurt of a short-lasting cycling race,​ the researchers proposed.

Additionally, as the number of participants in this trial was only nine, future studies should examine a larger number of subjects, they suggested.

Source: Nutrients​
Volume 10, issue 3, article no. 342, doi: 10.3390/nu10030342​​
Carbohydrate Mouth Rinse Fails to Improve Four-Kilometer Cycling Time Trial Performance”​
Authors:   Flávio O. Pires  et al​