Development of a “Cooling” Menthol Energy Gel for Endurance Athletes: Effect of Menthol Concentration on Acceptability and Preferences

Abstract

Menthol is effective at stimulating thermosensitive neurons that evoke pleasant cooling sensations. Internal application of menthol can be ergogenic for athletes, and hence, addition of menthol to sports nutrition products may be beneficial for athletes. The aim of this study was to develop a menthol energy gel for consumption during exercise and to determine acceptability and preferences for gels with different menthol concentrations. With a randomized, crossover, and double-blind placebo-controlled design, 40 endurance athletes (20 females) ingested an energy gel with a menthol additive at a high (0.5%; HIGH) or low concentration (0.1%; LOW), or a mint-flavored placebo (CON), on separate occasions during outdoor endurance training sessions. The athletes rated the gels for cooling sensation, mint flavor intensity, sweetness, and overall experience and provided feedback. Results are reported as median (interquartile range). Both menthol gels successfully delivered a cooling sensation, with a significantly greater response for HIGH (5.0 [4.0–5.0]) compared with LOW (3.5 [3.0–4.0]; p = .022) and CON (1.0 [1.0–2.0]; p < .0005), and LOW compared with CON (p < .0005). Ratings of mint flavor intensity followed the same trend as cooling sensation, while ratings of overall experience were significantly worse for HIGH (2.0 [1.0–3.0]) compared with LOW (4.0 [2.0–4.0]; p = .001) and CON (4.0 [3.0–4.0]; p < .0005). An energy gel with the addition of menthol at 0.1–0.5% provides a cooling sensation for athletes with a dose–response when ingested during exercise. The 0.1% concentration is recommended to maximize the overall experience of the gel.

Perceptual and Physiological Responses to Carbohydrate and Menthol Mouth-Swilling Solutions: A Repeated Measures Cross-Over Preliminary Trial

“…Such findings may be of use to athletes undertaking heat acclimation training, whereby the heat stimulus may be actively applied, i.e., during exercise [65][66][67] or passively via hot water immersion [68][69][70] or a sauna [71] during recovery from exercise. Alternatively, in competition, this finding allows athletes to pursue complementary nutritionally and thermally ergogenic strategies [72], potentially mitigating commonly reported issues during prolonged exercise (in the heat) such as gastrointesti-nal distress [12,17,73] or taste fatigue [73]. This finding also has relevance to armed or emergency service personnel, who may have to report rapidly to situations in thermally challenging environments, potentially in varying states of nutritional preparedness.…”

Menthol Mouth Rinsing Maintains Relative Power Production during Three-Minute Maximal Cycling Performance in the Heat Compared to Cold Water and Placebo Rinsing

“…A further pertinent extension of the present work, which would incorporate elements of pacing and other applied and mechanistic factors would be to administer menthol to athletes who experience significant drafting effects e.g., as part of a team pursuit. Airflow appears critical in one’s experience of oropharyngeal sensations of cool and therefore menthol [ 35 , 62 ], thus if one were experiencing a significant drafting effect i.e., a reduction in wind resistance [ 77 , 78 ], the efficacy of menthol administration may be blunted but will still likely depend on other factors such as athlete preference and habituation to menthol and mentholated products, and TRPM8 receptor density [ 79 , 80 , 81 ].…”

Athlete perceptions of flavored, menthol-enhanced energy gels ingested prior to endurance exercise in the heat

“…0.1%, 0.3%, 0.5%, or 0.7%). These concentrations were determined based on previous work comparing menthol gels with low (0.1%) and high (0.5%) concentrations to estimate what would be acceptable and preferable [ 17 ]. The addition of natural citrus flavor was novel to the menthol/control gel formulation used in the current study.…”

“…Energy gels are another widely used practical nutrient delivery form for athletes. Previous work from our laboratory conducted on elite endurance athletes demonstrated that an energy gel with a menthol additive was acceptable at a 0.1% concentration and provided a significant cooling effect compared to a non-menthol, flavor-matched placebo gel [ 17 ]. At 0.5% concentration, the menthol gel produced a greater cooling effect than 0.1%; however, the overall experience was significantly lower, and feedback indicated that the mint flavor was ‘ too strong’ for a majority of the participants surveyed (i.e.…”