I ran on the treadmill for the first time with this bra this morning, and it was great! For someone who normally wears a 36DDD, the concept of no bounce and no chafing is amazing! I do agree that going up a band size was the right way to go, but I think I probably would want my regular cup size with this bra if I buy another one, which I probably will. I would give it 5 stars, but since I still had to wear a 2nd bra under it for a bit of separation and support, I gave it 4.