A review of evidence by a team of Canadian and U.S.-based researchers shows that for most people, using face masks during moderate to heavy exercise does not affect lung function.
The review, published in Annals of the American Thoracic Society, and referenced in guidance issued from the World Health Organization, examined the effects of various face masks and respirators on the respiratory system during physical activity. The researchers found that feelings of dyspnea, or shortness of breath, may be increased, but the actual physiological effects of face masks (measured through changes to gases in the blood such as oxygen and CO2) during physical activity were very small—often too small to be detected—even during heavy exercise.
“For moderate exercise for the average person, there is no evidence that it impacts performance. The lungs can handle whatever increased resistance is there with the face mask,” said Michael Stickland, a professor of medicine in the University of Alberta’s Faculty of Medicine & Dentistry and senior author of the review.
According to Stickland, masks warm the face, triggering a sensory perception that likely contributes to the feeling of breathlessness. The feeling is not reflected in the body’s physical response, though.
The researchers examined all available evidence for a wide variety of face masks, including cloth face coverings, surgical masks, N95 respirators and industrial respirators. According to Stickland, the team even examined the impact of self-contained breathing apparatus, or SCBA, used by firefighters in a smoky environment.
“It's a device that [functionally] increases the work of breathing,” said Stickland, who is also a member of the U of A’s Alberta Respiratory Centre, director of the G.F. MacDonald Centre for Lung Health and scientific director of the Respiratory Health Section of Alberta Health Services' Medicine Strategic Clinical Network. “SCBA has four to five times greater resistance than what would be experienced with a surgical face mask, and it was still found to have only a marginal impact on lung function during exercise.”
The researchers say the findings were consistent when also looking for differences based on an individual’s sex or age. The one exception may be those who have severe cardiopulmonary disease, for whom any added resistance and minor changes in the oxygen and CO2 in the blood may bring about considerably more dyspnea, affecting exercise capacity. In those cases, patients may want to discuss available options with their physician.
According to Stickland, the researchers hope the review brings clarity to the ongoing public discussion about the efficacy and safety of face masks during exercise.
“We hope this will help reduce the misinformation that is often found on social media around face masks,” said Stickland. “I know many of us would like to exercise again. Some people have suggested you shouldn't wear a mask because of a theoretical impairment that might occur, but our data suggests that’s not the case.
“If you have worn a mask now regularly, you probably don't even notice the perception of breathlessness anymore. The first few times you might, but after a while, it just becomes normal.”