1980 Most runners keep a formal journal in which to record their running experiences.
Some runners keep record of their diet, weight, how they felt, and so forth.
Keep whatever kind of journal you like but do attempt one, and from time to time record your resting heart rate. I am running for my life inspired by the Adida Indians of Central America. These hardy primitives are truly the aristocrats of distance running and an adult Adida can cover 100 miles nonstop at a pace that would fell an Olympic miler. And among the Adidas, heart disease is virtually unknown. In fact, the Adidas have no medical knowledge whatsoever.