Effects of a Cap-Mounted Portable Fan on Localized Skin Cooling and Perceived Weakness During Cycling in Hot-Humid Conditions

Rising heat exposure increases the risk of heat-related illness during physical activity and outdoor work, suggesting a need for an accessible cooling strategy. The aim of this study was to examine the effects of a portable fan on physiological responses, perceived heat stress, and cognitive function during exercise in hot-humid conditions. Ten participants completed two trials, with a fan (WF) and without a fan (WOF), cycling at 50% of Heart rate reserve (HRR) in a controlled chamber (30 °C, 70% relative humidity). Skin temperature was continuously measured on the forehead, neck, chest, and thigh, and core temperature was measured via a tympanic probe, at a sampling rate of 1 Hz. Forehead and chest temperatures were lower in WF at 15 and 30 min (p < 0.05), while heart rate and tympanic temperature were unchanged. Breathing rate was lower in WF at 30 min (p < 0.05). Stroop test response times improved following exercise, with no difference between conditions. The use of a portable fan reduced upper-body skin temperature and perceived weakness but did not affect overall cognitive performance during short-term exposure. These findings suggest that localized cooling may help manage localized thermal discomfort during short-term exercise in hot-humid conditions.