Thermoregulation and subjective thermal perception of N95 respirator users: Influence of significant workloads

ABSTRACT

Working under a significant metabolic rate while wearing an N95 mask increased the heat stress that users of protective clothing experienced. This study investigated in a climatic chamber preset at 25 degrees C and a relative humidity of 65% the changes in thermoregulation and thermal perception of 13 men and 12 women when performing exercises involving different metabolic consumption for 60 min first without wearing an N95 mask for 30 min and then donning a mask. The physiological parameters include the metabolic rate, tympanic temperature, heart rate, skin temperature, skin moisture, and transepidermal water loss (TEWL). Thermal perceptions, including thermal sensation, humidity sensation, thermal comfort, and thermal acceptance were surveyed. The results show that both N95 mask use and exercising contributed to vigorous thermoregulation, particularly in women. The tympanic temperature was between 35.5 degrees C and 36.5 degrees C during the experiment for both sexes. Skin temperature during the exercise with or without donning a mask was not influenced by the change in workload, indicating a balance in heat exchange between the body and ambient air. Skin moisture increased by 58.91% and 49.99% when the users of masks performed exercises involving moderate and very high metabolic rates, respectively, compared to levels when a mask was not worn. The TEWL of women and men when wearing a mask and jogging increased by 16.35% and 14.89%, respectively, compared to when not wearing the mask. These results suggests a potential thermal stress from using N95 masks and working in a warm environment when the users are not acclimatized.