Since it switched off it is not getting on

I too had this situation where my Gear Fit appeared to be 'Dead' even after charging for 24 hours, I noticed however that my Phone still had the Gear Fit Icon showing.

I disconnected the Bluetooth and reconnected and noticed it connected fine so I held the power button down on gear fit for around 5 seconds (maybe longer) and it appeared to perform a 'Soft Reset' and started up fine.