In my snooty elitist young-and-still-uninjured opinion, anyone "healthy" is able to run one mile (non-stop). I don't care how fast you run it. If you can't run one mile non-stop, you aren't in good physical condition.

Humans were made to run. We evolved to run slow and long. If you cannot do what your body, over centuries of evolution, became designed to do, then there is a problem.

That being said, I think a mile is a big mental barrier for people. I think a lot of people are physically capable of doing it but mentally do not believe they can. And if you don't think you can do it, you're much more likely to give up halfway through than to make yourself push the whole way.

Screw walking. Anyone can walk. Everyone should be able to walk long distances, no problem. Walking is a basic requirement. Hell, it's a fucking prerequisite for existence.

Running takes a little work and some discomfort. But that is about all. That, and enough stubborn-ness to push past your mental blocks.

If you are physically incapable of running one mile, something is wrong with your health. Health At Any Size - sure. If you can run one.