The Truth About Whether Face Masks Lower Oxygen Levels

As the pandemic continues, the need for wearing face masks to limit the spread of COVID-19 becomes more apparent. While some people refuse to wear face masks or carry around fraudulent "face mask exempt" cards that claim they are not legally required to wear masks due to health concerns, the Centers for Disease Control and Prevention urge everyone from ages 2 and up to wear a face covering in public. The exception to this guideline is "anyone who has trouble breathing, is unconscious, incapacitated, or otherwise unable to remove the mask without assistance."

While wearing a face mask is one of the most effective tools we have to slow the spread of the virus, some people are concerned that wearing a mask will prevent them from getting enough oxygen. This idea persists, and is one of the major reasons people don't wear face masks. But is there any truth to it? 

According to Dr. William Schaffner, a professor of infectious disease at Vanderbilt University and medical director of the National Foundation of Infectious Diseases, no. "Normal, healthy people can do quite energetic things while wearing the sorts of face coverings that we've been talking about in the context of COVID prevention," he told Today. "If they were injurious, they couldn't be recommended by the CDC, state or local health departments."

Kirsten Koehler, an aerosol scientist and associate professor of environmental health and engineering at Johns Hopkins Bloomberg School of Public Health, agreed that, while face masks can be uncomfortable and lead to someone feeling overheated, there's no risk of reduced oxygen flow. "Scientific studies are showing that there's no real important changes in C02 levels or oxygen levels even from wearing surgical masks," she said. "And fabric masks have better permeation for gases."

Schaffner added that wearing a mask might make breathing a little harder as "the mask is acting as a filter," but masks do not lower oxygen levels. While some people with conditions like asthma or chronic obstructive pulmonary disease may struggle to comfortably wear a face mask, it is especially important for them to wear a face covering in public as they are at higher risk for complications from COVID-19.

"I definitely recommend using a face mask for everyone in these times, especially for people with asthma and COPD," Dr. Neil Schachter, professor of medicine, pulmonary, critical care, and sleep medicine at Mount Sinai Hospital told CreakyJoints.