Effects of Wearing Facemasks During Brisk Walks: A COVID-19 Dilemma

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


J Am Board Fam Med. 2021;34(4):798-801. 

In This Article


In this controlled trial, we demonstrated that wearing a facemask during a 5-minute walk has mild effects on respiratory parameters, causing EtCO2 to increase more profoundly than walking without a mask. In addition, oxygen saturation decreases while walking briskly with a facemask.

Most values remained within normal limits, but a subset of participants reached abnormal levels. The consequences and clinical significance of these minor gas exchange abnormalities are unclear, yet several participants reported shortness of breath and dizziness while walking briskly with a mask. The relationship between these phenomena has to be further investigated. Notably, our evaluation tested healthy volunteers and lasted only 5 minutes in an air-conditioned room.

EtCO2 probably increases due to rebreathing of expired air "trapped" in the chamber formed between the mouth and the mask. During exercise and the inevitable increase in respiratory rate coupled with increased CO2 production, there was a clearing of trapped air that was probably less effective, and perhaps even further dampened by mask warmth and humidity. This activity also increases resistance and overall work of breathing, contributing to subjective sensations of breathlessness, and increased Borg scale. A recent article by Fikenzer et al[8] also demonstrated a marked negative impact of masks on exercise capacity.

These effects of breathing through a mask have not been thoroughly investigated. Kim et al[9] evaluated volunteers walking calmly for 1 hour wearing an N95 mask. They observed an increase in transcutaneous CO2 (with most results remaining within normal limits), but no change in oxygen saturation. Person et al[10] examined the effect of wearing a facemask on healthy individuals while performing a calm 6-Minute-Walk-Test. Distance walked, oxygen saturation, heart rate, and respiratory rate did not differ while wearing a mask. Samannan et al[11] recently reported a minor influence of masks on gas exchange in healthy volunteers, and COPD patients, performing 6-minute walk tests. Rebmann et al[12] evaluated nurses wearing facemasks and did not see any clinically relevant physiologic changes, although many subjective symptoms were reported.