i haven't been able to find this in Garmin's limited documentation on the web nor in any of the reviews.
i currently have a 935 where it seems that only the digital CIQ watch faces are capable of displaying 1hz HR data due to screen refresh/power constraints. i was hoping that Garmin's built in face might have this feature.
[i'm now considering the 945 since the 945 LTE doesn't really offer me any added functionality over the 945... my 935 altimeter has been wonky of late and i would love the map features of the 945]