Effectiveness of Topical Menthol as A Cooling Method During Exercise in A Recreational Runner Population

The goal of this clinical trial is to evaluate the effectiveness of topical menthol as a cooling method during exercise in a hot air environment in healthy adult recreational runners aged 18 to 45 years. The main questions it aims to answer are: What is the difference in thermal sensation between the topical menthol gel application and a placebo during exercise? How does the application of topical menthol affect body temperature, heart rate, and physical performance compared to a placebo? Researchers will compare a 4% Menthol gel to a placebo gel in a cross-over design to see if the menthol gel improves thermal sensation, regulates body temperature, and enhances physical performance and comfort. Participants will: 1. Undergo a screening process including a medical history review, physical examination, resting ECG, blood sugar test, and a Bleep fitness test. 2. Participate in two separate running activities at an athletic field, separated by a wash-out period of 7 days + 1 day.Have the assigned gel (menthol or placebo) applied to their neck, front upper arms, and front upper legs while running (specifically between kilometers 2.5 and 2.8). 3. Complete pre-run and post-run assessments measuring weight, skin and tympanic temperature, heart rate, vertical jump height, running duration, perceived exertion (RPE), thermal sensation, and comfort.