Which of course could be dangerous
It was shown on the trust me I'm a doctor show so I've had a google
www.telegraph.co.uk/technology/news/12086337/Fitbit-heart-rate-tracking-is-dangerously-inaccurate
Apparently the watch and hrm chest strap does work
So I guess fitbits is going to be a waste of time. And could well be dangerous if it's reading well under during sport/exercise