If they are big enough they will still get chaffed. Dated a marathon runner for a bit. Wet skin rubbing wet skin will get you every time lol.
When I ran in college we used band aids on our nipples.
@Mokvon Marathon and Cross Country runners are like in a whole other world lol. It was always fascinating to me. There were times she would run for a few miles think she was done then hang out for a bit and run some more. Her runners high must have been fun. I ran for a bit but I don't think I ever got to the runners high stage.