YouTube:
Bitchute:
Brighteon: https://www.brighteon.com/f1a685d0-135c-4486-b07d-985ae00d269d
Lbry.tv: https://lbry.tv/@adrianr:8/ep-105-masks-can-cause-hypoxia-and-how:f

If you watched my other video is wearing a mask dangerous:

Then you will understand the dangers of wearing a mask.

You should be able to demonstrate this using a pulse oximeter like this one:
https://amzn.to/2XIEeG1

Blood oxygen saturation levels below 90% are considered dangerous. With the pulse oximeter false readings can occur with nail polish particularly black, brown, blue, fluorescent lighting or with sickle cell disease.

With all that said it could still prove to be a useful tool.

Oxygen saturation:
https://en.wikipedia.org/wiki/Oxygen_saturation_(medicine)

As always please do your own research, thinking and draw your own conclusions.