Impact of cooling vests on the physiological and perceptual responses of firefighters in high-temperature and heat radiation environments
[Objective]In firefighting and rescue scenarios,firefighters often confront a combination of high-temperature,heat radiation,and physical exertion,frequently leading to heat stress reactions among firefighters and resulting in fainting,injuries,and casualties,which affects their physical and mental well-being.Moreover,thermal sensation and comfort significantly impact the operational efficiency of firefighters and the duration of effective rescue efforts.This analysis focused on the effectiveness of cooling vests in alleviating heat stress and improving thermal comfort for firefighters.Herein,we mitigate heat stress levels among firefighters,enhance the operational efficiency and the duration of emergency rescue operations,and validate the effectiveness of cooling vests.[Methods]This study utilized a high-temperature environmental chamber and silicon carbide radiant panel to construct a high-temperature and heat radiation experiment setup.Experiments were conducted in a composite environment at 35℃ and 2.5 kW/m2 heat radiation at two physical activity intensity levels,4.5 and 7.0 km/h.This study involved physiological experiments on the human body and the use of subjective questionnaires to investigate the impact of cooling vests on the physiological and subjective responses of firefighters.Physiological and perceived strain indices were employed for heat stress assessment,and the mitigating effect of cooling vests on the heat response of firefighters was quantified.[Results]Compared with the control group,the cooling vests significantly reduced the core temperature,skin temperature,heart rate,and sweating rate of the subjects.Under experimental conditions,the cooling vests lead to a maximum decrease of 0.21 ℃ in core temperature,a maximum average decrease of 0.24 ℃ in skin temperature,a maximum decrease of approximately 7 bpm in heart rate,and a reduction of 1.35 g/min in sweating rate;this effectively alleviated physiological stress.Moreover,the impact of the cooling vests on human thermal sensation was obvious during high-intensity physical activity.At 90 min during 7.0 km/h movement after 20 min,the thermal sensation value for the cooling vest group was 1.0 lower than that of the control group.Moreover,at 50 min during 4.5 km/h movement after 20 min,the thermal sensation value for the cooling vest group was reduced by 0.33 compared with that of the control group.This was consistent with and mutually corroborated the impact of cooling vests on core body temperature.In addition,cooling vests effectively improved the thermal comfort of the participants.Differences existed between the cooling vest and control groups,with the maximum thermal comfort difference being 0.67 at 50 min.However,this difference was significantly reduced compared with the thermal comfort of the torso region.At 90 min,the cooling vests resulted in a maximum decrease of 0.77 in the physiological strain index and a reduction of approximately 32％in the perceived strain index.[Conclusions]Improvements in the fabric of cooling vests for firefighting can enhance their performance in protecting against heat in heat radiation environments.Specifically,for firefighting scenarios involving high-intensity physical activity in high-temperature and heat radiation environments,efficient cooling methods and the use of lighter cooling materials should be considered.This study can serve as a reference for enhancing individual heat protection in firefighting gear and provide support for the development and improvement of cooling vests for firefighters.
high-temperature and heat radiation environmentfirefighterscooling vestsperceptual responsesthermal comfort
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