At our running club, we have an 85 YO man who was a good marathoner in his day - but he has slowed down considerably . However he NEVER stops when running. Today I stuck with him at the back of the pack for 8K at an average 9:30 mins per K. It was slow even for me -but we chatted along the entire way and NEVER stopped. About 1 hour and 15 minutes later I knew that I had gone on a run!! We got lots of looks from bystanders along this touristy beachside course - I guess that was not surprising seeing as how 155 years of experience was passing by them !!