I've worn mine on the inside since day one - on my right wrist (I'm left handed). Pulse seems pretty accurate - compared to my chest strap and Polar RCX5 watch/HRM, at least until above 120bpm, then the band gets a bit erratic. The band also is a little slower at updating the HR, when compared to a dedicated chest band system. I maintain if you workout at high BPM and need to monitor your heart, a chest strap is the way to go.