Wearing a mask when you’re out and about is now pretty much the norm everywhere you go.

Doctor’s appointment? Mask required. Off to get a haircut? Better have your mask with you. Masks are even recommended when you visit friends and family in the midst of the COVID-19 pandemic.

However, just because masks are heavily advocated for doesn’t mean everyone wants to wear one. In fact, many people complain that they can’t breathe through the mask and that their oxygen levels are probably at more harm than them even contracting the virus.

No one is arguing that wearing a mask can be rather uncomfortable and make it feel harder to breathe. But no one has really done any experiments on whether a mask truly affects your oxygen levels—until now.

One doctor named Megan Hall wanted to see if wearing masks affected people’s heart rates and oxygen levels. She decided to don four different masks for five minutes each to see if it were true.

Spoiler alert: It’s not. What Dr. Hall found was that her heart rate no her oxygen level were significantly affected by wearing a mask. Her results are below:

No mask: 98% oxygen, 64 heart rate

Surgical mask: 98% oxygen, 68 heart rate

N95 mask: 99% oxygen, 69 heart rate

N95 plus surgical mask, 99% oxygen, 69 heart rate

“There is no significant change in my oxygen saturation (or HR) in any scenario,” Dr. Hall concludes. “Though maybe inconvenient for some, you can still breathe.”

In a now-viral Facebook post, Dr. Hall encourages everyone—especially the skeptics—to continue to wear masks in public to help reduce the spread of COVID-19. It’s not just to protect your health, but to protect others. And since it doesn’t affect how you breathe, it doesn’t cause you any harm.

“As a physician, I urge you and ask you to please wear a mask to protect yourself and those who cannot safely wear a mask (many of my patients because they are under 2 years old),” she wrote.

If one doctor’s opinion doesn’t convince you, know that the CDC and the World Health Organization have also suggested wearing masks in public and that they don’t pose any danger to your breathing.

So why does it sometimes feel like our airways are constricted when wearing a mask? The answer is simple: It’s just because we’re not used to wearing masks. The more you wear them, the more comfortable they’ll feel on your face!

Do you wear a mask when out in public? Were you ever concerned about how it affected your oxygen or heart rate levels?