title: Relieving thermal discomfort: Effects of sprayed L-menthol on perception, performance, and time trial cycling in the heat.
abstract: L-menthol stimulates cutaneous thermoreceptors and induces cool sensations improving thermal comfort, but has been linked to heat storage responses; this could increase risk of heat illness during self-paced exercise in the heat. Therefore, L-menthol application could lead to a discrepancy between behavioral and autonomic thermoregulatory drivers. Eight male participants volunteered. They were familiarized and then completed two trials in hot conditions (33.5 °C, 33% relative humidity) where their t-shirt was sprayed with CONTROL-SPRAY or MENTHOL-SPRAY after 10 km (i.e., when they were hot and uncomfortable) of a 16.1-km cycling time trial (TT). Thermal perception [thermal sensation (TS) and comfort (TC)], thermal responses [rectal temperature (Trec ), skin temperature (Tskin )], perceived exertion (RPE), heart rate, pacing (power output), and TT completion time were measured. MENTHOL-SPRAY made participants feel cooler and more comfortable and resulted in lower RPE (i.e., less exertion) yet performance was unchanged [TT completion: CONTROL-SPRAY 32.4 (2.9) and MENTHOL-SPRAY 32.7 (3.0) min]. Trec rate of increase was 1.40 (0.60) and 1.45 (0.40) °C/h after CONTROL-SPRAY and MENTHOL-SPRAY application, which were not different. Spraying L-menthol toward the end of self-paced exercise in the heat improved perception, but did not alter performance and did not increase heat illness risk.
authors.affiliation: Department of Sport, Exercise and Rehabilitation, University of Northumbria, Newcastle upon Tyne, UK.
authors.forename: M J
authors.initials: MJ
authors.lastname: Barwood
authors.forename: J
authors.initials: J
authors.lastname: Corbett
authors.forename: K
authors.initials: K
authors.lastname: Thomas
authors.forename: P
authors.initials: P
authors.lastname: Twentyman
mesh_terms: D000279:Administration, Cutaneous; D000328:Adult; D054874:Athletic Performance / Q000502:physiology*; D001642:Bicycling / Q000502:physiology*; D001833:Body Temperature Regulation / Q000187:drug effects* / Q000502:physiology; D003879:Dermatologic Agents / Q000008:administration & dosage / Q000494:pharmacology*; D004311:Double-Blind Method; D006339:Heart Rate / Q000187:drug effects / Q000502:physiology; D006358:Hot Temperature / Q000009:adverse effects*; D006801:Humans; D008297:Male; D008610:Menthol / Q000008:administration & dosage / Q000494:pharmacology*; D010465:Perception / Q000187:drug effects*; D005082:Physical Exertion / Q000187:drug effects / Q000502:physiology; D013697:Thermosensing / Q000187:drug effects; D013997:Time Factors
chemical_list: D003879:Dermatologic Agents; D008610:Menthol
keywords: Thermoregulation; behavior; perceived exertion; sensation