My own take:
I take fitness/exercise probably more seriously than my golf game. My gym time is entirely geared toward physique development (isolated weight lifting). I can say confidently that my "brand' of fitness affects my golf negatively and vice versa. Not so much performance, but really how prepared my body feels to do one or the other. Playing 18 holes with a chest pump and DOMS from yesterday's leg workout adds a whole new element to the game managing pain, stiffness, soreness, etc. Then the flip-side would be golf generates its own set of aches when you're actively ill-preparing your body for it.