Interestingly, i can't find any of the articles that refute that... used to be plenty on google until about 2-3 weeks ago. All I was able to find were studies (over decades) indicating that whether a surgeon wore a mask or not, the number of infections during procedures did not change (if anthing, less infections when no mask was worn). That said, most of us prefer a masked surgeon, lol. And of course no hospital is going to want to deal with the legal ramifications of going maskless.
Since I cannot find articles (pretty annoying... even more so since ithought i'd bookmarked at least 1) indicating that O2 was reduced, I can't make the argument on scientific grounds and hafta stand down. The science presented here is compelling.
And yet I'd ask you to go have a talk with someone who works retail 10 hours a day wearing mask while talking with people and climbing ladders and moving a lot of heavy boxes. I have. They talk about getting light headed. They talk about splitting headaches. And there isn't a one of them who won't tell you their breathing is impaired and they can't wait to leave their store, rip, the mask off, and breathe fresh air. So perhaps the argument isn't that O2 is reduced (or CO2 increased)... rather that breathing thru a mask while under exertion for long periods of time (for the average Joe) is significantly more difficult and grinds a person down.
Sitting at a desk, taking a stroll, probably not so much. [And if it doesn't impair breathing, why do 99% of people at the gym forgoe it as soon as they begin their workout? Is it to avoid the sweat? Or is it that breathing is simply easier? Or are we all just rebellious bastards? lol]
[Curious if anyone knows... when that person wearing a mask while driving lost consciousness and smashed up their car, all the docs were saying wearing a mask while driving was a bad idea. I'm guessing that opinion has changed? As of July, the even the CDC advised against it... so I'd ask if O2 isn't affected, why would it be an issue at all?
https://downshiftmagazine.com/2020/05/why-are-you-wearing-a-mask-while-driving-alone/
More intriguing is that the great state of PA (run by Ma Kettle her...um, self) instructs you NOT to wear a mask while driving. Odd. Why not? They don't say. But enjoy the article, the memes, and the twitter piece that instructs us on proper mask usage. Ahem.]