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

• Main Authors: Roxanne M Vogel (Author), Megan LR Ross (Author), Christian Swann (Author), Jessica E Rothwell (Author), Christopher J Stevens (Author)
• Format: Book
• Published: Taylor & Francis Group, 2022-12-01T00:00:00Z.
• Subjects: article
• Online Access: Connect to this object online.
• Notes: 1550-2783; 10.1080/15502783.2022.2117995
• Keywords: endurance; cooling; thermal perception; supplement; mint; Nutrition. Foods and food supply; TX341-641; Sports medicine; RC1200-1245
• Source: Journal of the International Society of Sports Nutrition, Vol 19, Iss 1, Pp 580-592 (2022)

Background L-menthol evokes a cooling sensation by activating cold sensing cation channels. Menthol-enhanced fluids can be ergogenic during exercise in the heat by improving thermal perception; hence, the addition of menthol to energy gels may benefit athletes. Previously, unflavored menthol gels were deemed acceptable at 0.1% concentration, but no research has been undertaken on menthol gels with additional flavoring. Therefore, we determined athlete perceptions of flavored energy gels with different menthol concentrations. Methods With a randomized, crossover, double-blind, placebo-controlled design, 27 athletes (34.8 ± 6.7 y, 9 females) ingested an energy gel with either 0.1%, 0.3%, 0.5%, or 0.7% menthol concentration, or a non-menthol, flavor-matched placebo (CON), on separate occasions before outdoor exercise. Gels were rated for cooling sensation, irritation, flavor, and overall experience on 100-point sensory and hedonic labeled magnitude scales. The duration of any cooling sensation was also reported. Results All menthol gels 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. Irritation 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 rated above a 'mild-moderate' intensity. The menthol gels delivered a significantly longer cooling sensation duration (12.3-19.6 min) versus CON (2.2 ± 4.8 min) with no difference between menthol gels. Conclusion A flavored menthol energy gel at 0.1-0.7% concentration provides a cooling sensation for athletes when ingested before exercise. The 0.5% concentration is recommended to maximize the cooling sensation whilst minimizing irritation.