Ophir Bar-On, MD; Yulia Gendler, PhD; Patrick Stafler, MD; Hagit Levine, MD; Guy Steuer, MD; Einat Shmueli, MD; Dario Prais, MD; Meir Mei-Zahav, MD
Corresponding Author: Meir Mei-Zahav, MD; Schneider Children's Medical Center of Israel. Email: mmeizahav@gmail.com
Section: Brief Report
Publication Date: July 23, 2021
Background: During the COVID-19 pandemic, wearing facemasks became obligatory worldwide. Objectives: To evaluate effects of facemasks on gas exchange. Methods: Healthy adults were assessed at rest, and during slow and brisk 5-minute walks, with and without masks. We monitored O2-saturation, EtCO2, heart and respiratory rates. Participants graded their subjective difficulty (Borg's Perceived Exertion Scale), and completed individual sensations questionnaire. Results: Twenty-one participants, median age 38yrs (range 29-57yrs) were recruited. At rest, all vital signs remained normal, without and with masks. However, during slow and brisk walks, EtCO2 increased; the rise was significantly higher while wearing masks: slow walk, mean EtCO2(mmHg) change +4.5±2.4 versus +2.9±2.3, p=.004; brisk walk EtCO2 change +8.4±3.0 versus +6.2±4.0, p=.009, with and without masks, respectively. Wearing masks was also associated with higher proportions of participant hypercarbia (EtCO2=46-49mmHg) compared to walking without masks, although this was only partially significant. Mean O2-saturation remained stable (98%) while walking without masks, but decreased by 1.2±2.2% while walking briskly with a mask (p=.01). Mild desaturation (O2=93-96%) was noted during brisk walks among 43% participants with masks, compared to only 14% without masks (p=.08). Borg's scale increased significantly while walking with a mask, for both slow and brisk walks (p<.001). Sensations of difficulty breathing and shortness of breath were more common while walking with masks. Conclusion: While important to prevent viral spread, wearing facemasks during brisk 5-minute walks might be associated with mild hypercarbia and desaturation. The clinical significance of these minor gas exchange abnormalities is unclear and should be further investigated.