The Effect of Wearing a Face Mask on Body Temperature

Objective To investigate the effect of wearing a face mask on body temperature in healthy subjects. Methods The study was of repeated measures design. It was conducted from July to August 2003 in two accident & emergency departments on Hong Kong Island. Staff of the two departments, who were free from any active disease at the time of measurement, were recruited. Their body temperature (oral and aural) was measured while they were not wearing a mask and at 30 minutes after they had worn a mask (either surgical mask or N95 mask). Paired t-test was used for significance testing. Pearson product-moment correlation coefficient was calculated to elucidate the relationship between oral and aural temperature measurement. Results Ninety-three subjects were included. Oral temperature was significantly higher when a mask was worn (p=0.002, 95% CI 0.06–0.26). When considered separately, only those wearing N95 mask demonstrated such significance (p=0.005, 95% CI 0.088–0.454). The correlation coefficient for oral/aural temperature measurements was 0.219 (without mask, p=0.035) and 0.169 (with mask, p=0.104). Conclusion Wearing a face mask may increase the oral temperature in healthy subjects. However, the difference may not be clinically significant.