First it disappeared from Bluetooth. I then reminded myself of the tethered reboot which I have used in the past, successfully. All the various tricks don't work. Checking to make sure I am on the latest Mac iOS, no conflict with another Apple device eg iPad, turning them all off and then on in the prescribed order and even seeing if letting it flash the logo on and off forever (or charge forever - did both) cures it. Nada. Started March 14 so ca 48 hours along. Very frustrating because it's used to log exercise with gradations of exertion, sleep patterns and O2 levels. This one replaced a Charge 3 so the issue has nothing to do with unfamiliarity with the product line or how to use it. Oh, now that I think about it also started telling me that the lost contact had to do with the internet. So long as I have cell connection, that's nonsense but despite the warning it was actually updating to the App and Power Sync. That started early in the week or perhaps late the week before. Finally the periodicity seems to be ~9 seconds logo and then ~1-2 seconds blank...
