Well, you are obviously way above my level, but I am 34yo, and readily run up my heart rate to 175-180bpm on the trainer for over an hour at a time with no ill affects so far. Unless I am seriously doing something wrong without realizing it? Of course I measure my hr by taking my pulse manually. I don't have a monitor yet. But I do know how to count.
I would agree, it is good to take a day with a differant type of workout after such an intense ride. Maybe some spinning, or just do some other activity you enjoy. But unless you are used to it, you may not want to push too hard for another day or two.