I am not sure if the Fitbit is actually blinking; it's that with each pedal stroke the little green light is going around and around and it looks like blinking.
NY, glad to see I am not the only one. I stopped wearing my HR monitor many years ago, after having none of them work well. All I learned is that my HR is higher than most. I truly am someone who can use RPE and very accurately predict what my HR is from that.
I set an alarm (clock radio) on the days I get up super early for the gym, but I really don't need it. My brain wakes me up about 5 minutes or more before any alarm i set. It is very rare my alarm wakes me up. I just don't sleep later than 6 AM, unless I've been out until midnight.