Not OP, but it has to be a walk with no headphones for me. As I walk, thoughts seem to bubble up from my subconscious and present themselves for consideration. This doesn’t happen as often if I’m listening to music.

I don’t walk but I run 60-120 min 4-5x a week and could not imagine doing so with headphones. Firmly believe we need time away from the constant stimulation of modern life.