Today: The Sun's Tracy Ross talks with Dimity McDowell, a longtime runner who one day couldn't take the pain of it anymore, and began the difficult task of weaning herself from her runner's high -- a legitimate addiction. A former contributing editor at Runners World, McDowell chronicles that journey and more in her new book, The 27th Mile: How to Smooth the Rough Transition Out of Your Running Years, which she'll be reading from and speaking about at the Tattered Cover in Denver tonight. We start our conversation with Dimity explaining what a stress fracture is -- she had several over her running career and they were part of what led her to stop.