Physical and Perceptual Cooling with Beverages to Increase Cycle Performance in a Tropical Climate

Abstract

PurposeThis study compares the effects of neutral temperature, cold and ice-slush beverages, with and without 0.5% menthol on cycling performance, core temperature (Tco) and stress responses in a tropical climate (hot and humid conditions).MethodsTwelve trained male cyclists/triathletes completed six 20-km exercise trials against the clock in 30.7°C±0.8°C and 78%±0.03% relative humidity. Before and after warm-up, and before exercise and every 5 km during exercise, athletes drank 190 mL of either aromatized (i.e., with 0.5 mL of menthol (5 gr/L)) or a non-aromatized beverage (neutral temperature: 23°C±0.1°C, cold: 3°C±0.1°C, or ice-slush: −1°C±0.7°C). During the trials, heart rate (HR) was continuously monitored, whereas core temperature (Tco), thermal comfort (TC), thermal sensation (TS) and rate of perceived exertion (RPE) were measured before and after warm-up, every 5 km of exercise, and at the end of exercise and after recovery.ResultsBoth the beverage aroma (P<0.02) and beverage temperature (P<0.02) had significant and positive effects on performance, which was considerably better with ice-slush than with a neutral temperature beverage, whatever the aroma (P<0.002), and with menthol vs non-menthol (P<0.02). The best performances were obtained with ice-slush/menthol and cold/menthol, as opposed to neutral/menthol. No differences were noted in HR and Tco between trials.ConclusionCold water or ice-slush with menthol aroma seems to be the most effective beverage for endurance exercise in a tropical climate. Further studies are needed to explore its effects in field competition.

Optimizing Ice Slurry Ingestion for Endurance Performance in the Heat: A Meta-Analysis

“…Th e specifi c exclusion criteria were as follows: no measurement of endurance performance (n= 9); measurement of uncompensable work performance, that is, fi refi ghters (n=4); existence of additional cooling strategies that the main eff ect of ice slurry ingestion cannot be isolated (n=3); outcome assessed by power outputs, repeated sprints, intermittent exercise, or graded exercise to predict endurance performance (n=8); and core temperature at the end of endurance performance test was below 38°C (n=1). One additional study (Riera, Trong, Sinnapah, & Hue, 2014) was identifi ed through cross-referencing eligible studies. Th erefore, a total of 16 eligible studies were included in the meta-analysis (Burdon, Hoon, Johnson, Chapman, & O'Connor, 2013;Ihsan, Landers, Brearley, & Peeling, 2010;Jeff ries, Goldsmith, & Waldron, 2018;Maunder, Laursen, & Kilding, 2017;Riera et al, 2014;Siegel et al, 2010;Siegel, Mate, Watson, Nosaka, & Laursen, 2012;Stanley, Leveritt, & Peake, 2010;Stevens, Dascombe, Boyko, Sculley, & Callister, 2013;Stevens et al, 2016;Takeshima, Onitsuka, Xinyan, & Hasegawa, 2017;Tran Trong, Riera, Rinaldi, Briki, & Hue, 2015;.…”

The Development of a Menthol Solution for Use during Sport and Exercise

“…Habitual menthol use may alter the threshold at which TRPM8 channels and the trigeminal nerve are stimulated [37][38][39][40], ultimately habituating thermal sensation [37,38]. Despite no statistically significant differences in the present investigation, menthol concentrations of 0.095-0.105% may lead to small increases in trigeminal stimulation, concomitantly conferring benefits such as an increase in ventilation [3,16], reduced thermal sensation [18] and thirst [14], and improved thermal comfort [9] when exposed to the oral cavity.…”

“…All menthol-containing studies [9,10,[16][17][18][19]31] have employed a repeated exposure during the exercise bout-this is quantified via time or distance. Better understanding the time course of menthol mouth swilling responses, and the potential impact of concentrations upon these, would provide insight into possible limitations in application for menthol-containing strategies.…”

“…Other ergogenic effects are likely dependent upon the exercise mode undertaken [2][3][4][5] and active ingredients within the swill, e.g., Caffeine [2,6], Carbohydrate [7,8] or Menthol [3]. These ingredients may also be combined with other ergogenic strategies to maximise the influence upon physiological and psychological determinants of fatigue [9][10][11].…”

“…A more contemporary application of menthol has been that of an ergogenic aid which can be applied topically [15], used as a mouth swill [16][17][18] or ingested alongside ice slurry [9,10,19]. This use is fitting, with menthol shown to increase the drive to breathe [20], elevate ventilation [21] and attenuate thirst [13], along with eliciting sensations of coolness and freshness that may alleviate thermal symptoms during exercise [3].…”