I mean anecdotally, I did a very similar thing to that for about 8 years straight, and towards the tail end I joined a roller derby team and my athletic endurance was better than ever, and at its best when I was fully lit. Great for lifting weights too.

Found it to be wonderful for practicing things you already mostly knew how to do, but more challenging for learning entirely new things. But lung capacity was an absolute non-issue for me, personally. I always attributed that to the extra deep breaths and breath-holding that went with the hobby.