Experts weigh in on whether wearing face masks limits your oxygen intake

There have been many changes in our lives since the COVID-19 pandemic made its way to the U.S. We’ve seen schools and businesses shut down for months as state and local governments enacted stay-at-home orders to keep people safe and healthy. And now, many places are trying to re-open while following health guidelines from the Centers for Disease Control and Prevention (CDC), including those on hand-washing and wearing face masks.

The CDC specifically recommends that everyone ages 2 and up should “wear cloth face coverings in public settings and when around people who don’t live in your household.” In its recommendation, the CDC cites 19 different scientific studies that provide evidence of how wearing cloth face masks can reduce the spread of the COVID-19 virus.


Despite this evidence, some wonder if wearing face masks for prolonged periods of time can cause a reduction in oxygen intake by blocking the nose and mouth.

There are several articles online that claim wearing a face mask can expose asthmatics to hypoxia, which is oxygen deprivation at the tissue level of the body. Another, less serious condition known as hypoxemia is also possible. This is when someone experiences low oxygen in their blood. Symptoms of hypoxemia include headaches, a fast heart rate, wheezing, confusion and coughing according to the Cleveland Clinic.

Meanwhile, Professor Gregory Erhabor, the founder of the Asthma and Chest Foundation, told Healthwise that he believes wearing a face mask can be risky for certain populations with lung diseases, such as asthma.

“If asthmatics who have moderate-to-severe asthma put on masks,” he said, “it may result in hypoxia, with subsequent development of difficulty in breathing.”

In addition to concerns about reduced oxygen intake, another worry some people have is the build-up of carbon dioxide (hypercapnia) behind a cloth face mask.

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With all of these alleged health risks, it can be easy to be alarmed. But it’s important to know that many medical experts and scientific studies show that cloth face masks do not reduce oxygen intake for the majority of people.

“There is no risk of hypercapnia (CO2 retention) in healthy adults who use face coverings, including medical and cloth face masks, as well as N95s,” Dr. Robert Glatter, an emergency physician at Lenox Hill Hospital, New York, told Healthline. “Carbon dioxide molecules freely diffuse through the masks, allowing normal gas exchange while breathing.”

Cloth face masks are porous, which allows oxygen and carbon dioxide to flow through the barrier and allow the important exchange of gases that keeps us healthy. They also do not fit around our faces tightly enough to restrict airflow. In other words, when we breathe out, the carbon dioxide can escape freely both through the mask and around the sides, making it next to impossible for an excessive build-up of carbon dioxide for healthy people.

“This simply won’t happen unless there is an air-tight fit and you rebreathe your air,” Professor Keith Neal, an infectious disease expert, told the BBC.

If you have a chronic lung condition, it is always wise to consult your doctor regarding your risk for contracting COVID-19, and to solicit their advice regarding face coverings. But, for most of us, putting on that cloth face mask can help prevent the spread of the virus until a vaccine is discovered.