On the use of personal cooling suits to mitigate heat strain of mascot actors in a hot and humid environment

Mascot actors have to wear bulky, heavy and low permeability costumes during a performance. Documented work and headline news have consistently demonstrated that severe heat illnesses associated with mascot costumes are the major health problem among mascot actors. Though various personal cooling systems (PCSs) have been developed to mitigate the heat stress of people wearing protective clothing, no research has been reported on the actual cooling benefit of using PCSs under mascot costumes. Thus, in this work, a newly developed hybrid personal cooling suit based with dry ice and ventilation fans (HYB), and a water-cooling suit (WCS) were chosen to examine their actual cooling performances on mascot actors while performing a moderate activity in a hot and humid condition (i.e., 34 ± 0.5 °C, RH = 78 ± 5%, wet-bulb globe temperature [WBGT] = 31.8 °C). The total trial duration was 60 min, which comprised 40-min walking at 4.0 km/h followed by 20-min resting at room temperature (i.e., 24 ± 1 °C, RH = 55 ± 5%, WBGT = 20.1 °C). The present study showed that both HYB and WCS successfully prevented the core temperature of mascot wearers from rising above 38.0 °C throughout the 60-min trials. In contrast, the wearers’ core temperature reached 38.0 °C in about 35 min in CON (i.e., CONTROL, no cooling). HYB and WCS could also bring remarkable cooling to the body surface so that mean skin temperatures stayed <36.5 °C. Moreover, both HYB and WCS decreased the total sweat production by over 34.2–46.0% compared to CON. Heart rates in HYB and WCS were also decreased by 12 and 20 beats/min compared to that of CON. Therefore, physiological strain index and perceptual responses have been greatly improved by using HYB and WCS. It is thus concluded that the two cooling suits can be used to mitigate heat stress on mascot wearers during a one-hour performance in the studied condition. It was noted that the cooling performance of WCS was greatly deteriorated approaching the end of the trials. Thus, mascot actors are advised to replace cooling sources during the resting period in order to ensure the WCS suit could still bring pronounced body cooling benefits for upcoming work-rest cycles.