Nipples color?

I used to have pink nipples, but over sometime (not sure how long) a year? My areoles became a pale color, as if I’m getting no circulation color. I don’t exercise. I recently Did some bench presses for 3 days and I noticed my right areola had gotten more pink and brighter but my left didn’t get much color if any. My left breast is the smaller one with the nipple is pointed slightly down while my right is the “normal” bigger one. But that’s another matter, I’m more “concerned” about the color.. is there a reason? Is it from lack of exercise, poor blood circulation, etc..