But you know what? Pulse oximeters are pretty cheap nowadays. Try it for yourself.
If someone holds their breath long enough to cause hypoxia when inhaling nitrous oxide, they have other problems. You can easily hold your breath 1-2 minutes while sitting on a couch without experiencing hypoxia. If you're experiencing euphoria as strong as what nitrous oxide causes from hypoxia, you're basically about to die.
You don't even need to research it, the lived experience of being in a dentist office with mixed oxygen and nitrous produces the recreational effects - if it was mostly hypoxia, having oxygen mixed in would have a greatly diminished "recreational" effect.
I mean, it is true most people doing it recreationally are giving themselves mild to severe hypoxia, but that doesn't mean the effect is caused by hypoxia
I believe in medical settings it's delivered in a mixture with O2, but in recreational settings it's usually inhaled directly.
I see a lot more talk about the risks of vitamin B12 depletion, and not much talk about O2 deprivation, so not sure if everyone else is crazy or if it's me who is the crazy one.