fyi. I have given up on aw use in gym. For me it does not report heart rate in real time. It is always delayed in response to changes in bpm as to make it unreliable. When Polar reports sudden increase in bpm aw often drops to an absurdly low figure. I have tried different modes..walk, other etc because i read that aw samples differently for different modes. True or not I do not know. Anyway i dont see how an average bpm can be Meaningful. I tried aw on a long walk. Even then it would suddenly report 68 bpm when i knew it was 110 by Polar. Then suddenly report the real bpm. Aw is great for many things. But not for heart monitoring imho. I use app heartwatch. But i have tried the built in heart monitor with same result. Sorry Apple. Back to Polar and that annoying strap i was hoping to avoid.