Comparison of the Physiological Effects of Wearing a Dust Mask and a Breath – Synchronized Powered Air-Purifying Respirator – a Comparative Crossover Study

ackground: Few studies have examined the physiological effects of wearing respiratory protective equipment in Japan. The aim of this study was to evaluate the physiological effects of wearing a dust mask (replacement–type) and a breath–synchronized powered air purifying respirator (BS–PAPR). Methods: Eight non-smoking healthy men aged 20 to 39 years participated in this study. We randomly divided the subjects into three groups and conducted a comparative crossover study with a counterbalanced design to control for experimental order effects. The participants underwent exercise tests under three conditions: not wearing a mask, wearing a dust mask and wearing a BS-PAPR. We measured several physiological indicators, including respiration rate, fractional gas concentration in the respirators (fraction of expired carbon dioxide (FECO2) and fraction of inspired carbon dioxide (FICO2)), blood pressure, heart rate, double products and New Borg scale score. These parameters were analyzed using a repeated analysis of variance. Results: Comparison among the three conditions showed no significant difference in blood pressure, heart rate, double products, respiratory rate, or degree of subjective fatigue. However, the respiratory rate tended to be lower when wearing a BS–PAPR than when wearing a dust mask. Similarly, the New Borg scale score tended to be lower when wearing a BS–PAPR than when wearing a dust mask. FECO2 and FICO2 values were significantly lower when wearing a BS–PAPR than when wearing a dust mask before and after the exercise test, although there was no significant difference during exercise. Conclusions: Our findings suggest that use of a BS–PAPR may reduce the burden on the respiratory system due to exercise loading, and improve subjective fatigue compared to a regular dust mask.