"Exercise performance can be improved by application of non-thermally cooling menthol... Internal application appears to be the best strategy to improve performance."
Menthol is an organic compound with non-thermal cooling properties that has been shown to relieve thermal strain associated with exercise in the heat; however, its effects on performance have not been systematically analyzed. The aims were to determine the effects of menthol applied (1) internally and (2) externally on exercise performance and thermal sensation.
A search was performed using various databases in August 2018. The studies were screened using search criteria for eligibility. Thirteen peer-reviewed articles were identified for inclusion in a primary analysis on the effect of menthol on exercise performance; subsequently eleven of these articles were included in a secondary analysis on the effect of menthol on thermal sensation during exercise. A sub-analysis examining the application method was also performed.
Menthol improved overall exercise performance (Hedges’ g = 0.33, 95% CI −0.00, 0.65 P = 0.05), demonstrating greater effects when applied internally (Hedges’ g = 0.40, 95% CI 0.04, 0.76, P = 0.03). Thermal sensation was also lowered overall across all studies (Hedges’ g = −0.54, 95% CI −0.67, −0.42, P < 0.001).
Exercise performance can be improved by application of non-thermally cooling menthol, which also reduces perceptual measures of thermal sensation. Internal application appears to be the best strategy to improve performance.