Thermal perception during exercise is known to influence endurance performance and the onset of fatigue. L-menthol, an organic compound derived from peppermint, evokes a cooling sensation through its action on TRPM8 channels which also respond to cold stimuli. Recent work identified that the internal application of menthol-enhanced fluids can be ergogenic during exercise in the heat. Hence, the addition of menthol to energy gels may be practical and beneficial for athletes. PURPOSE: To determine athlete acceptability and preferences for flavored energy gels with different menthol concentrations. METHODS: With a randomized, crossover, and double-blind placebo-controlled design, 27 endurance athletes (34.8±6.7 y, BMI: 21.7±1.6 kg·m-2, 9 female) ingested an energy gel with a menthol additive at relative concentrations: low (0.1%), medium-low (0.3%), medium-high (0.5%), high (0.7%), or a non-menthol, flavor-matched placebo (CON), on separate days before outdoor running sessions. Athletes rated the gels for cooling sensation, irritation (tingling/burning), flavor, and overall experience on 100-point sensory and hedonic labeled magnitude scales. The duration of any cooling sensation was also reported. Repeated measures ANOVAs with a Bonferroni adjustment for pairwise comparisons were used to determine differences. RESULTS: All menthol gels successfully delivered a greater cooling sensation compared to CON (7.4±8.1 AU) with a significantly greater response for 0.7% (59.9±20.5 AU) and 0.5% (57.7±21.8 AU), compared to all others, which were both rated “moderate-strong” for intensity. Irritation intensity was higher for all menthol gels compared to CON (3.4±7.2 AU), and for 0.7% compared to 0.1% (31.1±31.0 vs 16.3±21.0 AU, p=0.041), with none reported higher than a “mild-moderate” intensity. The menthol gels delivered a significantly longer cooling duration (range: 12.3-19.6 min) compared to CON (2.2±4.8 min) with no significant difference between menthol gels. Ratings of overall experience and flavor were not different between gels (p>.05). CONCLUSION: A flavored energy gel with the addition of menthol at 0.1-0.7% provides a cooling sensation for athletes when ingested before exercise. The 0.5% concentration is recommended to maximize the cooling sensation of the gel whilst minimizing irritation.



To view the content in your browser, please download Adobe Reader or, alternately,
you may Download the file to your hard drive.

NOTE: The latest versions of Adobe Reader do not support viewing PDF files within Firefox on Mac OS and if you are using a modern (Intel) Mac, there is no official plugin for viewing PDF files within the browser window.