A new study suggests that face masks have a negligible negative effect on the levels of carbon dioxide and oxygen that a person breathes.
The findings even hold true for individuals with chronic obstructive pulmonary disease (COPD).
The research, which appears in the journal Annals of the American Thoracic Society, contributes to dispelling some of the myths surrounding the use of face masks in the context of the ongoing COVID-19 pandemic.
As the world gains access to more information about SARS-CoV-2, the virus that causes COVID-19, scientists have become increasingly convinced that masks can help reduce its spread.
The primary way that SARS-CoV-2 transmits involves viral particles entering a person’s respiratory tract. This typically happens after another person coughs, sneezes, or speaks near them, producing droplets or aerosols that transport the virus.
Consequently, face masks play an important role in reducing exposure to the virus and limiting the amount of the virus that a person can project toward others.
There is a growing consensus about the value of face masks in reducing the spread of SARS-CoV-2, though this has not always been the case.
Initially, little was known about the new virus and policy had to be developed based on the best available evidence, following scientific models that drew on data from earlier epidemics involving similar viruses.
As a consequence, guidance about mask wearing has varied from country to country, and some major health bodies, including the World Health Organization (WHO), have changed their advice over time.
In many ways, these changes and discrepancies are inevitable when providing advice about an urgent public health crisis while scientists are continually discovering new information. Dogmatically sticking to a position despite the changing evidence or offering advice when there is little evidence to justify it are unlikely to be better approaches.
However, research has shown that significant changes in official guidance reduce people’s trust in the science that is the basis of the policy.
In addition, the use of face masks has become a political battleground, with vocal proponents on the right denouncing enforced mask wearing, either as an infringement of freedom or a suspected element in a broad conspiracy that COVID-19 was mobilized or fabricated.
In this context, some people have proposed that face masks are a threat to public health, supposing that the masks reduce the amount of inhaled oxygen or increase the amount of inhaled carbon dioxide.
To test this theory, the researchers behind the present small study recruited 15 house staff physicians, who had no health issues affecting their lungs, and 15 veterans with COPD.
The veterans were in the hospital so that doctors could check their oxygen levels as part of their regular COPD monitoring.
The monitoring involved, among other things, blood oxygen levels checked with a blood test before and after a 6-minute walking exercise. This exercise was done while wearing a mask, as per hospital protocol during a pandemic.
The researchers used a LifeSense monitor to check the baseline room air, and then continually took