Have you thought of trying to pick up another language? Started learning Spanish 4 years ago and now I can go on vacation and have conversations with locals. Also, I’m more interested in their local history because I can read it/listen to it in Spanish and practice the language at the same time.
Also, don’t they need to run to move food through their digestive tract? Or to force themselves to cough if they have something stuck in their lungs? I think there is some sort of dependency of basic functions that relies on the movement of their lungs/stomach going back and forth while running that they can’t easily do if they just stand in one place all day