Are you not concerned that an oxygen enriched atmosphere will INCREASE THE GENERATION OF REACTIVE OXYGEN SPECIES?
As a separate protocol I inhale 90% Oxygen in order to stimulate HIF. ROS are a problem if they stay high for too long. A short time does not deplete the anti-oxidants in the mitochondria and stimulates HIF.
However, the evidence I have seen is that you need at least 60% Oxygen to have that effect. I have just started reading a book on HIF which takes some effort, but looks good to me.
You can download it for free as a PDF from this page:
https://www.mdpi.com...fview/book/4839
Note
https://www.ncbi.nlm...les/PMC5908316/
"Free radicals are generated during normal cellular function and are part of the natural physiological process of all living beings [1–3]. They normally act as both beneficial and toxic compounds, since they can be either helpful or harmful for the body [4]. "