Mine has improved, and continues to. I'm just saying that not everyone is John Havlicek (famous for running non-stop throughout every game of his NBA career, with his pulse rate staying at levels mere mortals only see while asleep). I'll never be Hondo Havlicek, so I have to take a different approach. My relative (especially for my size) lack of lung capacity was also a limiting factor playing trombone. I'm wise enough at 55 to know that I can improve, but that 'part of me' will just never be great when compared to others at a similar fitness level.