@jlk12 Hi there. Just a thought. I don't know why either. I do YouTube exercises almost every day and such a difference. I also have arthritis and that is magic to do exercises.
There are lots of easy easy videos to start with. I do one in particular as the lady goes full steam ahead. As she ways if you can only do 5 reps instead of the 10 then do that etc.
Just put in exercises for copd. I do seated as never was to co-ordinated at at 80 I am even less LOL Hope that could help. Just monitor yourself and at least try. Might be challenging at first but trust me in time you will be amazed and maybe rather quickly. Greetings from Canada