Study: Face masks unlikely to cause carbon dioxide poisoning

Credit: AJC

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Medical experts say it's important to wear a mask in public.

Credit: AJC

Research finds overexposure unlikely even in patients with lung disease

New research out of Miami contradicts some people’s belief that wearing a face mask could lead to carbon dioxide poisoning.

Despite the CDC director telling the Senate that wearing a face mask might offer better protection against COVID-19 than a vaccine would, many people still resist or refuse to cover their faces.

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During the coronavirus pandemic, the researchers wrote in a press release, “the wearing of face masks has become a highly political issue with some individuals falsely claiming that wearing face masks may be putting people’s health at risk.”

The study, published in the Annals of the American Thoracic Society, shows otherwise.

Dr. Michael Campos and his co-authors at the University of Miami Miller School of Medicine and at Jackson Memorial Hospital in Miami assessed problems with gas exchange, which is changes in oxygen level or carbon dioxide levels.

The researchers examined both healthy individuals and veterans with chronic obstructive pulmonary disease, or COPD, before and while using surgical masks.

“We show that the effects are minimal at most even in people with very severe lung impairment,” Campos said.

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“Although we did not measure changes in tidal volume or minute ventilation, this data find that gas exchange is not significantly affected by the use of surgical mask, even in subjects with severe lung impairment,” the researchers wrote.

As for the feeling of breathlessness that some healthy people may experience, Campos explained: “Dyspnea, the feeling of shortness of breath, felt with masks by some is not synonymous of alterations in gas exchange. It likely occurs from restriction of air flow with the mask in particular when higher ventilation is needed (on exertion).”

The researchers also said wearing a mask too tight can increase that feeling of breathlessness. “The solution is simply to slow down or remove the mask if you are at a safe distance from other people,” they said.

The study came about after reports of a public hearing in Florida during which people commented that masks were putting lives in danger. The researchers could find no data on the effects of surgical masks on gas exchange.

“We acknowledge that our observations may be limited by sample size, however our population offers a clear signal on the nil effect of surgical masks on relevant physiological changes in gas exchange under routine circumstances (prolonged rest, brief walking),” the authors wrote. “It is important to inform the public that the discomfort associated with mask use should not lead to unsubstantiated safety concerns as this may attenuate the application of a practice proven to improve public health.”

“The public should not believe that masks kill,” Campos added.

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“As growing evidence indicates that asymptomatic individuals can fuel the spread of COVID-19, universal mask use needs to be vigorously enforced in community settings, particularly now that we are facing a pandemic with minimal proven therapeutic interventions,” the researchers concluded.

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