What stats will be trainable?

So with the option to use exercise equipment being added. There has been talk to add exercise as a mechanic to the game. So my question mainly to the developers is:

What things and stats are you planning or should be improved by your character doing much more physical exercise and getting fitter during the apocalypse. I heard that strength as well as stamina regen and max stamina would be improved by higher endurance but what about dex? You would expect someone who moves a lot to have joints in better condition than when the apocalypse began as well that stretches exercise like yoga can make you more flexible.