So the chest strap battery in my conventional Polar heart rate monitor (used for fitness) has expired. While contemplating replacement I noted that there are a few new 'fitness bot' type devices that you wear on your wrist and they track all sorts of data (from fitness output to sleeping patterns). I know Nike and Jawbone make one.
You can then upload the data and use it in various ways.
Is anyone using such a device? What brand? Does it actually work? And what are you primarily using it for?
