Effects of masks on physiological and thermal responses of college students during outdoor activities

Abstract

In the post COVID-19 era, people have adjusted to coexistence with viruses and air pollution, and masks have become basic personal protective equipment. However, we know little about the physiological and thermal feedback when wearing masks and performing outdoor activities varying in intensity. We combined mask types (no mask, surgical, N95, and cloth) and activity intensities (light, moderate, and vigorous) to investigate personal physiological and thermal responses in outdoor environments. We had four principal findings: 1) perioral temperature (Talocal) was the highest under cloth masks and perioral relative humidity (RHlocal) was the highest under cloth or N95 masks during moderate and vigorous intensity activities; 2) “breathing resistance” scores were the highest at all stages when wearing masks; 3) wearing masks had a positive effect on the decrease of mean skin temperature (MST), and this effect was the greatest for surgical masks; and 4) during exercise, thermal sensation vote (TSV) was mainly influenced by Talocal and RHlocal in the dead space under masks. TSV was primarily affected by RHlocal and ΔAH under surgical and cloth masks, while TSV was primarily influenced by Tg under N95 masks. Our findings provide basic information supporting mask selections linked to activity intensity in outdoor settings.