Hr in 60's while asleep. drops to low 50's after waking, while sedentary, post coffee. cardio 5x week. any concern?

Yes: How are you checking your heart rate while asleep? Your heart rate is likely a sign of your regular cardio exercising and good shape. If you are not dizzy, passing out when you stand up or having chest pains- have at it.

Sounds like you are: very well athletically conditioned. In the absence of symptoms of dizziness, chest pain or physical limitation this is all normal. Keep up the good life style choices!