fast miles vs. slow miles

[Charles]

Beginner's question:
Where is the line between fast miles and slow miles? How does a novice know where to draw the line?

[April G]

I think of it as slow=easy, conversational, comfortable and fast=somewhat uncomfortable, lungs are working--not wanting to talk much

[Eric Day]

  April.
But I would put it like this:

Slow : Breathing almost 'normal'; having fun; How was your day?; don't want to finish.

Fast : Breathing hard (can I get another set of lungs?); fun? (dang, why do I run?); DON'T TALK TO ME; in pain; want to finish.