Because I had radiation treatment along my neck and jaw line, I had to undergo 60 days of hyperbaric chamber treatment before I could have a dental bridge installed. (10 years later)
That was 5 years ago, and while I remain active, I sure haven't seen any slow down in my aging process.
Did you have 60 sessions over 90 days?
I think any effects probably only last as long as you keep doing the treatments. If you built a giant hyperbaric house to live in and never left it, then you might see lasting effects.
And just who recommended that and what were his/her credentials?