@josh The easiest way is to breath carbogen, which is a 95/5 mix of oxygen and CO2. Carbogen is an old hack (a hack only because mainstream medicine disallows its use by trivializing it while exaggerating its dangers) dating a century back.
I've used a carbogen machine of an earlier version made by Carbogenetics.com. It has been very helpful in getting me to recover from sickness. Simply put, it is vital in getting the optimal metabolism restored that allows the body to heal itself from illness. Imho, it is the reason mainstream medicine bans it.
It cost $700 and worth spending on when compared to how much more we spend on useless supplements and keep taking them just because.
Breathing carbogen and sleeping in it like on oxygen as used in hospitals is safe. The worst that can happen is developing respiratory acidosis. But like anything, it helps not to be a dumb user. As using it correctly is not rocket science, and listening to AMA propaganda makes one dumber and sicker ( like the scam of CPAP respiratory therapy).
The only knock I have on the unit is Steve being controlled by shysters. He limits his machine to 30 minutes usage per use, to keep himself from patients suing him, for an unlikely fail which would likely be used by the establishment and the complicit Talmudist press to frame him like what they did to Chauvin using George Floyd.