It concluded that the nitrogen in ambient air slightly but measurable impairs human performance compared with a non-anesthetic gas such as helium. This seems l

It concluded that the nitrogen in ambient air slightly but measurable impairs human performance compared with a non-anesthetic gas such as helium. This seems like a massive reach. Is it not possible the body is just perceiving that something is "wrong" about its current situation while breathing helium and is activating a threat response? The study authors didn't even bother to monitor heart rate, let alone blood concentrations of adrenalin and cortisol. This might have been a neat study in 1975 but it is not nearly rigorous enough.