Flex vs. Charge HR Sleep Tracking

[Zzcatcher5]

I currently have a fitbit flex, but I'm considering getting a Charge HR now that I'm a fitbit superuser. I love tracking everything--especially sleep. 

There is one point that I'm not 100% clear on with Charge HR and sleep. If the Charge HR tracks your heart rate continuously, shouldn't it use both your movement and your heart rate data to track sleep, making it more accurate than a flex, that just uses movement?

Yet, none of the literature available on the Charge HR seems to confirm or deny this fact. If I knew for sure that it did, I would be at the store today! Add this to your literature, fitbit!

[Cherlese]

I have the charge HR.  I love it. I don't know why it wouldn't use your HR to track sleep... I just assumed it does... I would think it's way more accurate than the flex, but then I've never owned a flex.  

[SunsetRunner]

Agree, Charge sleep calculations should be more transparent. I have had a flex and a charge, both had reported similar sleep patterns so I'm not sure it's more than the accelerometer at work.