692 BO53 – Effects of rinsing a menthol solution in physical, physiological, and perceptual responses of football referees during intermittent exercise in hot and humid environment

Background Intermittent exercise in hot and humid environments may increase thermoregulatory and physiological strain; physical performance and arousal levels can be negatively affected. Rinsing a menthol solution has been proposed as a non-thermic strategy to improve exercise performance in the heat. Objective To test if rinsing a menthol solution affects physical, physiological, and perceptual responses during intermittent exercise in hot and humid environments in football referees. Design Randomized single-blinded, counterbalanced, crossover trial. Setting Indoor laboratory setting, with temperatures ranging from 33.6 to 35.4°C and relative humidity ranging from 58.0 to 63.5%. Participants Nine non-heat-acclimated highly trained male football referees (aged 33.4±5.2 years). Interventions The participants performed two trials of a 45-minute intermittent exercise protocol (Soccer Aerobic Fitness Test, SAFT-45) in hot and humid conditions. In each trial, the participants were given 1 of 2 beverages before the warm-up (pre-cooling): a 0.01% menthol solution or a placebo noncaloric solution, both at room temperature. Main outcome measurements Total distance covered, rate of perceived exertion (RPE), core temperature and heart rate were monitored during the protocol. Thermal sensation, thermal comfort, and perceived thirst were measured at rest and after three 15-minute intermittent exercise blocks. Results The distance covered and RPE were not affected between trials (p>0.05). Core temperature and heart rate increased over time in both trials (p<0.001), but no differences were detected between trials (p>0.05). Thermal sensation and thermal comfort improved immediately after rinsing oral menthol (p<0.05), but no differences were observed between trials at any other time points. Perceived thirst was not different between trials (p>0.05). Conclusions The results of the present study showed that rinsing oral menthol did not influence physical, physiological, and perceptual responses in football referees during 45 minutes of intermittent exercise in hot and humid environments.