Do Face Mask Affect Oxygen Levels?


CLEVELAND, Ohio. (Ivanhoe Newswire)—Vaccinated Americans can now feel comfortable  shedding their masks indoors, according to CDC guidelines although some states and businesses may still require them and some of the country’s top docs, including Doctor Anthony Fauci, say masks may make seasonal returns to prevent colds and the flu. More on a new study measuring oxygen levels for mask-wearers.

Over the past year, Americans have covered up to prevent COVID from spreading, but many people have been concerned masks would cause breathing issues. Researchers at University Hospitals in Cleveland studied oxygen levels in adult mask-wearing volunteers to measure the impact on their respiratory and cardiovascular systems.

“We used a special medical probe that attaches to the forehead and it measures the oxygen level, the subject’s carbon dioxide level and also measures the heart rate too,” described Steven Shein, MD, chief of pediatric critical care at University Hospitals Rainbow Babies & Children’s Hospital.

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Doctors ran the tests under three conditions. They had participants sit quietly and then walk briskly without a mask, raising their heart rate, on average, 30 percent. Then the participants repeated the sequence with a cloth mask, and again with a surgical mask.

“We thought it was really important to test both cloth masks and surgical masks. And importantly, we had people bring in their own cloth masks. So, this was not some like special thing that it was like, you know, super thin. In both parts of this study, both with the cloth mask and with the surgical mask, we didn’t find any difference. Heart rate stayed the same. Oxygen level stayed the same and carbon dioxide levels all stayed the same,” stated Dr. Shein.

Researchers say the risk to the general mask-wearing adult population of having abnormal oxygen or carbon dioxide levels is near zero.

The scientists say one-third of the participants also reported having a chronic condition, like asthma, and still registered normal oxygen levels during the study.

Contributors to this news report include: Cyndy McGrath, Executive & Field Producer; Kirk Manson, Videographer; Roque Correa, Editor.

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REPORT:       MB #4915

BACKGROUND OF WEARING MASKS: Prior to the COVID-19 pandemic, the efficacy of community mask wearing to reduce the spread of respiratory infections was controversial because there was no solid relevant data to support their use. During the pandemic, the scientific evidence has increased. Compelling data now demonstrates that community mask wearing is an effective nonpharmacologic intervention to reduce the spread of this infection, especially as source control to prevent spread from infected persons, but also as protection to reduce wearers’ exposure to infection.


MASK WEARING REDUCES SPREADING OF DISEASES: Community mask wearing substantially reduces transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Masks prevent infected persons from exposing others to SARS-CoV-2 by blocking exhalation of virus-containing droplets into the air. This aspect of mask wearing is especially important because it is estimated that at least 50% or more of transmissions are from persons who never develop symptoms or those who are in the pre-symptomatic phase of the COVID-19 illness. In recent laboratory experiments, multilayer cloth masks were more effective than single-layer masks, blocking as much as 50% to 70% of exhaled small droplets and particles. Masks also protect uninfected wearers. Masks form a barrier to large respiratory droplets that could land on exposed mucous membranes of the eye, nose, and mouth. Masks can partially filter out small droplets and particles from inhaled air. Multiple layers of fabric and fabrics with higher thread counts improve filtration.


NEW RESEARCH ON THE PROTECTION OF MASK WEARING: Scientists at the CDC’s National Institute for Occupational Safety and Health tested a variety of face coverings for their ability to prevent the outward spread of particles from a simulated cough. N95 respirators performed the best, blocking 99% of the particles, while medical masks blocked 59% and a cloth mask blocked 51%. The only covering that failed to do much of anything was a face shield, which stopped just 2%. In another experiment, researchers in Japan evaluated how well different masks on two mannequins that faced one other reduced exposure to the coronavirus. Cotton or surgical masks on the mannequin releasing the virus cut the amount of exposure to the other by 50% or more. If only the exposed mannequin wore such a mask, the protective effect was smaller, but if both wore a mask, transmission decreased by 60% to 70%.





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Doctor Q and A

Read the entire Doctor Q&A for Steven Shein, MD, chief of pediatric critical care

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