Yes, I improved a lot since I started.

This is my second try to go through the course. The first time I failed in week 4 and lost motivation and quit. But I was over 2 minutes there already.
So I think I will get there again.
But I didnt smoke at this time, and I guess that is a big disadvantage.

Yeah I am not sure if I actually do a hour but I will do some extra breathing today.

I can only recomned giving it a try. The worst you have to loose is a bit of time but so much to gain.