This study aimed to clarify the effects of the following cooling garments on performance during and after vigorous, heart-rate-clamped exercise under hot and humid conditions: base layers made of cross-shaped fibers (C), sugar alcohol-printed base layers (S), and a combination of S with a fan-attached jacket (S+F). Fifteen healthy male participants wore the cooling garments and rested for 20 min in a room set to ~30°C and ~60% relative humidity. The participants then completed a 20-min cycle ergometer exercise with heart rate clamped at 65% of heart rate reserve and rated their perceived exertion (RPE). Before and after exercise, we assessed thermal, comfort, and wetness sensations and measured body temperature, vertical jump height, ground reaction force during rising from the chair, visual reaction time, and the Stroop interference. Cooler sensations were consistently reported in the order of S+F, S, and C. Despite the lowest RPE, pedaling load was highest in S+F. Sweat loss was comparable among the conditions, while garment sweat absorption and post-exercise skin temperature were lowest in S+F. These results suggest that S+F improves endurance performance under hot and humid conditions through efficient evaporative heat loss mainly facilitated by increased airflow from the fans.
Ota et al. (Fri,) studied this question.