>>519639605
This would actually make sense then
the treatments are just enough concentrations (with perfectly healthy proportions of oxygen)
to trigger fight or flight
the adrenal system activates, all sorts of fun metabolic stuff happens with mitochondria, and the person (in a sense) forcibly becomes healthier.
Particularly when done in a safe environment where individuals are entirely in control, it becomes a bit of anxiety training. Helping people deal with the FEELINGS of panic, and practicing mental fortitude to remain calm despite them.
See: Iceman. Wim Hoff.
Ignore much of the mumbojumo. The breathing exercises do exactly this. Hyper oxygenate, then hypo oxygenate. CO2 builds in the system, and triggers the same effect - even though you still have plenty of oxygen in your system to avoid (much) retardation
Anyway, point here is there has been a lot of clinical study on Wim Hoff's breathing exercise, and it is legit.
Except in the case of a breathable CO2 cell, you can always have enough oxygen, while still triggering the 'panic' response, all while exercising the exact same measures of self control - and benefiting from the immune/metabolic benefits (possibly).
Seems completely legit. I don't see any reason many issues couldn't be addressed by simple application of breathing high CO2 (given sufficient oxygen) in a therapeutic regimen. Maybe not literally everything listed, but placebo works, and you absolutely will feel something breathing CO2. I'm not entirely sold the drowning experience is just CO2, but sure. Granting your point, I see all of this as exceptionally plausible.