Originally Posted by Richard Cranium

There's a lot going on in that statement. There are mental constructs that humans endeavor to understand. They are called "dreams."
If you are riding a bicycle at 71 - I would have thought you had already acquired the maturity to know how much - and how hard - bicycle riding should be for a given day, or days.
If you do have a specific event in which you feel a need to excel - then ask your doctor or friends that know you and your riding ability whether the event is worth the training effort.

I noodle around most of the time - but I sucked it up last year and road a 6:20 Century in October - I could have gone faster, but I could have hurt myself as well. A man has got to know his limitations.........