My wife and I just finished watching on television the original Disney movie, "The Incredible Journey." The movie is the story of two dogs and a cat who traveled 200 miles to their new home. They didn't know where their human family was, but they knew by instinct that it was west. As I watched the movie, I related to the old bull terrier, Bodger. He paced himself and knew when to go and when to stop and rest. At times, I think, "I won't go running today." Then, I think of Bodger who never stopped until he had completed the 200 miles and found his human family. I think, "If old Bodger can make 200 miles, this old runner can make seven miles."
At age 76, I think of myself as an old man. However, here is a web page about people who are really old. The link was sent to me by Allen Young, author of the article. I recently read about a man who is 100 and who recently completed a full marathon, using a combination of jogging and walking. So, at age 76, I have a way to go before I'm "old."