[gardenfelder]

Rem sleep is typically measured in a sleep lab with many sensors, including EEG sensors - which do not exist on the wrist devices; inferring Rem is thus difficult. To me, it's just a kind of "relative" reading: think "rest state", and I care about it changing from time to time.

I upgraded to a Charge 5 from Charge 4, even though I happen to own an iWatch as well. Big mistake.

Charge 5 is happy to beep sms (morse code) from time to time when my cell phone picks up text messages. In the day time, that's fine, buf 4am in the fucking morning? There's no damned way to turn it off.

I am not aware of a skin temperature reading on it, though it does do an EKG-like reading, just like the iWatch. No clue whether it will phone 911 if my ticker gets funky; iWatch is known to do that.

I think I'd rather go back to a Charge 4, if only to get rid of text messages. I really don't need them - especially in the middle of the night.