Effects of face masks on oxygen saturation at graded exercise intensities

Context: Mask wearing to mitigate the spread of COVID-19 and other viral infections may raise concerns on the effects of face masks on breathing and cardiopulmonary health. Non-evidence-based apprehensions may limit the use of masks in public.

Objectives: We will assess the parameters related to heart and lung physiology between healthy male and female adults exposed to wearing face masks (or not) under conditions of rest and graded exercise.

Methods: We performed a cross-sectional study including 20 male and 20 female adults who met our inclusion criteria. Adults with underlying respiratory and cardiac conditions were excluded. Physiologic parameters were measured while the participants underwent three activity levels (10 min each) in a randomly assigned order: rest, walking, and stair climbing. Each activity level was conducted under three mask conditions: no mask, surgical mask, and N95 respirator. Heart rate (HR) and blood oxygen saturation (SpO₂) were recorded via pulse oximeter after each activity. Perceived exertion was recorded utilizing a Borg 15-point scale. A mixed-effects analysis of variance (ANOVA) was utilized to interpret the results.

Results: A significant increase in perceived exertion was reported for N95 users (p<0.0001). There was also a significant increase in mean HR for N95 users in comparison to no-mask users (p=0.0031). The mean SpO₂ in females was higher than males under rest and walking conditions (p=0.0055). There was no change in SpO₂ between mask type overall, nor between mask type vs. exercise intensity, nor between mask type and sex.

Conclusions: Our findings provide evidence that surgical masks and N95 respirators do not influence SpO₂ at rest or during exercise.