Will a piece of flooring laying on top of another piece, under exercise machine to prevent flooring damage, discolor floor color?

Hello Mike - Thank you for the inquiry. No - not necessarily. It won't discolor the vinyl planks - unless there are windows without window treatments to block out natural sun light. As far as damage, we are not sure what kind of exercise equipment you are referring to. We would recommend using foam gym mats of some sort for this. Hope this helps - Thank You -