@chan56 The NY Times article @Effi references is titled “Masks Work. Really. We’ll Show You How” Google that phrase and the interactive article is the first hit.
I don’t know about operating rooms, but dentists, ObGyns and many other doctors in non-surgical settings wear masks for hours on end without special training or oxygenation.
Can you point to some research that shows the damages that wearing masks does? People on here keep referencing it, but I have a hard time finding anything other than shadey YouTube videos. I am very interested in this topic and what the results of the studies are. My shul enforced mask wearing the entire Yom Kippur and there were people from ages 12 to 75 who davened (while fasting!) Shacharis through Mussaf for close to four hours straight wearing a mask the entire time. I wonder what health issues they encountered while doing that and whether I should tell them to go see a doctor to check for low oxygenated blood.