Do Face Masks Reduce Your Oxygen? No, And Stop Saying They Do

Let’s be clear: in the vast majority of cases, wearing a face mask to prevent the spread of COVID-19 will not lower your oxygen levels. 

Yet people continue to spread the myth. So-called “anti-mask” groups have been spreading misinformation about mask-wearing , suggesting that a face mask limits your body’s ability to take in oxygen and expel carbon dioxide. 

As mask-wearing when social distancing is not possible continues to become more prevalent across Canada, with cities like Toronto and Calgary adopting mandatory mask policies , it’s important to separate fact from fiction.

Claims that masks “limit your oxygen” or negatively impact your health are a bunch of nonsense. 

According to the American Lung Association, which is really the expert when it comes to lungs and whatnot, “there is absolutely no scientific evidence that mask wearing or physical distancing weakens the immune system.”

Want another expert opinion? The World Health Organization says that while wearing a mask can be uncomfortable, it does not lower your oxygen levels.

“The prolonged use of medical masks can be uncomfortable. However, it does not lead to CO2 intoxication nor oxygen deficiency,” says the WHO. “While wearing a medical mask, make sure it fits properly and that it is tight enough to allow you to breathe normally. Do not reuse a disposable mask and always change it as soon as it gets damp.”

Want to hear it from an on-the-ground doctor? Here’s Dr. Hannah Barham-Brown proving that masks don’t lower your oxygen levels.

“Haven’t passed out yet,” Barham-Brown says while demonstrating her oxygen levels remained the same. 

Not convinced? Here’s an anesthesiologist doing the same thing. 

Now, all of these statements are in reference to a classic surgical mask worn properly. That means over your nose and mouth, none of this down around your chin nonsense.

But the same is true for cloth face masks too.

Dr. Tom Lawton, an intensive care unit doctor in the U.K., decided to run a half marathon in a face mask to prove it doesn’t impact oxygen levels and raise money for food banks there.

He conducted a poll on Twitter to determine what type of mask he should wear on the run, with the classic cloth mask winning out.

“As an intensive care doctor dealing with some of the worst of the COVID-19 pandemic I am massively in favour of anything that might keep us all safe,” he wrote. “If I can run 16-21 miles masked, you can probably make it round the shops.”

Lawton, a former triathlete, ran to and from his hospital job wearing a homemade cloth face mask made from a pillowcase and curtains. And his  oxygen levels stayed near 98 per cent the whole way. 

“Final verdict was 22.6 miles in a mask (8 miles, then just over 14), breathing enough oxygen for about 10 calm people all the way,” Lawton wrote after completing his run. “The mask didn’t come off at all (no food or drink) - and oxygen levels were stubbornly 98% every time I checked. Please feel free to cite this when anyone suggests they’re bad for you, and stay safe - and COVID-free.”

Lawton even took some time to myth-bust some of the strangest feedback to his run.

He also ended up raising £2,876 (about C$5,000) for food banks. 

Just wear a mask, y’all. Because it’s working. A recent U.S.-wide study showed that community mask-wearing actually does make a difference when it comes to the spread of the novel coronavirus. 

To be clear, there are a select few people who can’t wear masks. According to the U.S. Centers for Disease Control, “cloth face coverings should not be placed on young children under age 2, anyone who has trouble breathing, or is unconscious, incapacitated, or otherwise unable to remove the mask without assistance.”

That’s why mask-wearing isn’t being strictly enforced. But everyone else, you should be wearing masks in places public health officials have recommended. In many cities, like Toronto and Calgary, that includes all indoor public spaces like stores and public transit.

And know that even if you’re running a marathon, you’ll still probably be fine.