Does the Subway arrive at my door?
If the streets are very busy, the pollution bad, the tunnels smell like piss etc, then that is the problem.
Small amounts of moderate exercise every day are a lot better than going to the gym (by car, usually) for a hard workout.
I’d rather read a book on the sofa, but you can’t walk while sitting on the sofa.
But these are all things that can (and should) be fixed.