New bangle 2 user, have questions!

Hi! :)

1 . i would like to turn off the bluetooth when I don't need it (I don't use the messaging notice feature). Does turning off BLE in settings turn off the bluetooth radio completely?

I think for most intents and purposes, yes. But not when on the DFU bootloader before Espruino firmware is loaded on the watch - this way you can always restore the watch if something goes badly. Hopefully someone will correct me if I'm wrong.

This comment on another conversation may be interesting (don't know if it's accurate still): https://forum.espruino.com/conversations/376607/#16555865

3 . I'm interested in my heart rate when i am doing exercise, but not when I am at work, watching movie etc. So I would like my heartrate to be measured dynamically - e.g. every 10 minutes when my heartrate is at rest (50-80), every 3 minutes when it goes up (e.g. im walking in the heat, 80-100) and constantly when I am actively exercising (100+). I get this feature isn't in the health app now, how easy would it be to add? Seems to me a good function - instead of having to manually update the frequency before a workout. Could also save on battery when its not needed.

I don't think there's something quite like that dynamic hrm logging, but should be possible. One could discuss whether to add the functionality to the health app as an option or if it should be a new app (personally I'd probably say add to the health app).

4 . I will be synching with the gadgetbridge app every few days (when i turn bluetooth on). Is there an app or a way to store all the health data (heart rate, sleep, steps) and synch it to the app when it connects to the app? Is the steps data stored anywhere on the device? Is there an app that stores this data?

There is activity fetching to Gadgetbridge, currently sending heart rate, steps and movement info that was stored by the health app. Gadgetbridge fetches data from the last sync date up to the latest available data. Sleep data is logged by the sleeplog app, but syncing it to Gadgetbridge is not implemented yet (would be a neat addition if you're up for a challange maybe). Activity fetching was added with this PR I think.