Walgreens Activity Monitor Advanced

Hi, first time user here. Just bought the Bio today. How tight does it have to be on the wrist? I am assuming that the underside has to make contact with the wrist for tracking and the heart etc.. When i take it off, i can see dents where the squares underneath the watch are.

Same here! I've tried loosening out, but the readings don't seem to be as accurate as when the band is tight enough to leave indents in my wrist. It's not enough to hurt, but it does get a bit uncomfortable at times.