My morning resting heart rate (MRHR) is between 46 and 55, depending on recent training load. I use 48 as my "normal," so if I'm 54 and up, I figure I need to take it easy for a few days. That's personal. Yes, I'd say the 65 means "take it easy."

Interestingly, I'll get a more elevated MRHR from several days of long mileage at moderate HR. Just one hard day usually lowers my MRHR for a few days.