02-24-2016 01:17
02-24-2016 01:17
02-24-2016 09:29
02-24-2016 09:29
Hi @JSanJo welcome to the Community! if on the Fitbit app, you have the "All day sync" activated, as long as your iPhone is on and your tracker is close enough (up to 20 feet) to it, it'll automatically sync. However that feature consumes the battery of your Fitbit Flex and you iPhone more quickly. Now regarding the silent alarms, only if you are going to set a new one or you are going to edit one that is already setting you need to turn the phone on, because you have to sync for the changes to be saved. Otherwise, it doesn't matter, as long as your tracker has battery, the silent alarm will vibrate. In addition, I suggest you to take a look of this article "How do I manage silent alarms".
I'll be around if you have further questions.