2.4. Description the water and menthol/ethanol solutions
The ethanol/menthol solution was a proprietary blend made by
Physicool Ltd™ (London, U. K.) and was composed of 0.2%
(16.8 mg) menthol, 20% (16 mL) ethanol, combined with 64 mL of
water; as menthol is not soluble in water, the ethanol suspended
the menthol in solution. When applied on the upper body (excluding
the hands, head and neck), which represents approximately
55% of the total surface area (Yu et al., 2010), this equated
to 1.68 mg of menthol per 100 cm2 surface area for the average
male with a total body surface area of 1.76 m2. The water-only
condition used tap water. All solutions were stored at room temperature
(approximately 20 °C) and transferred into the environmental
chamber three hours before testing, where they remained
until they were applied. The water or menthol/ethanol solutions
were measured in a graduated cylinder to 64 mL and poured in a
sealed waterproof pouch. Long sleeve breathable shirts were then
placed in the sealed pouch and soaked with the interventionspecific
liquid until all fluid was absorbed into the fabric. Participants