Totally non-scientific, experiential situation that happened last week that I witnessed (from shore):
Recreational diver plans a dive on a single tank to 110' with air and gets lost, confused, etc. and hits 121' and incurs 4 mins of deco plus a safety stop. Diver realizes that he is almost OOG and so her and buddy go straight up (controlled, but a bit fast) to the surface, omitting all stops of any kind.
Back on shore I offer O2, but it is refused. Both divers remain non-symptomatic (one says he is "normal tired"), and after a couple of hours one diver goes home and the other "normal tired" one makes a second dive. On the second dive, the diver does a max depth of 60' for 10 mins, does 10 mins from 60' to 20', and then does 30 mins at 20'. After the second dive he claims to feel much more energetic and less tired than he did after the first dive.
I'm not making any claims here, just relating the story, because the diver mentioned claims he reduced bubbles on the second dive and "cleaned up."