Is the treadmill just across the door?

Those things that don't talk about feng shui are put wherever it is convenient. Of course, if you are a local tyrant, invite a feng shui swindler to your home and let him teach you. It depends on the overall layout.

Personally, facing the French window or balcony, you can see the best scenery outside. You don't like running with a wall in front, do you?