Most health organizations have argued that wearing a face mask helps slow the spread of the COVID-19. Still, some critics have argued masks can cause carbon dioxide poisoning by trapping CO2. Now, a new study showed this is actually very unlikely to happen, with the researchers stressing the importance of wearing a mask.

Michael Campos from the Miami Veterans Administration Medical Center and his team analyzed the breathing patterns of 15 healthy physicians without lung conditions and 15 veterans living with chronic obstructive pulmonary disease (COPD). They compared these before and after wearing a mask through a six-minute walking test.

During the walk, individuals with severe COPD experienced decreased oxygenation, as expected by the researchers. However, at 5 and 30 minutes after the walk, researchers found no major changes in oxygen saturation or carbon dioxide levels between the groups.

“We show that the effects are minimal at most even in people with very severe lung impairment,” Campos said in a statement. Asked about the discomfort felt by some people when wearing a mask, he added: “The feeling of shortness of breath, felt with masks by some is not synonymous with alterations in gas exchange.”

If you’re walking briskly up an incline, for example, you may experience feelings of breathlessness. An overly tight mask may also increase these. The solution is simply to slow down or remove the mask if you are at a safe distance from other people, Campos argued.

The use of face masks has become a highly politicized issue throughout the pandemic, with some individuals falsely claiming that wearing a mask can negatively impact a person’s breathing and put their health at risk. Scientists have attempted to combat these theories, reassuring that face masks can safely prevent COVID-19.

Despite these efforts, some people are still not persuaded. Anti-mask groups have been holding rallies in cities in several countries in objection to pandemic-related restrictions. Demonstrators have continuously questioned the effectiveness of mask-wearing and social distancing practices.

The impetus behind Campos’ research came after reports of a public hearing in Florida where individuals made provocative comments, namely that wearing masks were putting lives at risk and finding out that no data on the effects of surgical masks on gas exchange was available. That has now changed with this new study.

“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),” wrote the authors. “It is important to inform the public that the discomfort associated with mask use should not lead to unsubstantiated safety concerns.”

The study was published in the journal Annals of the American Thoracic Society.