Some of the young folks have found this thread a "fun" place to mock the problems of us old folks. You think being "old" is a result of being "lazy"? Nope...it doesn't work that way.
Sadly, the sort of shape and health someone is in at age 60, 70, or 80 has mostly to do with picking the right grandparents. Riding a bike is NOT a cure for getting old. Where are the guys who won the Tour de France fifty years ago? Well, most of them are dead. They picked really bad grandparents.
But, I do find riding a bike makes being old a bit more enjoyable. A ten mile walk would leave me sore and tired...a ten mile bike ride makes me feel like Truman is president again.