It’s 6:15 in the morning and the pavement is flying beneath me. With each stride through the dark, frosty morning, I’m gobbling up yards of San Vicente Boulevard as I head for the final stretch back to the office. Even though I’m cold and clammy, there’s a certain exhilaration knowing that there aren’t many others up at this hour, let alone preparing for an event like the marathon: 26.2 miles of grueling, energy-sapping punishment. I’d wanted to run a marathon for more than twenty years. But even during the fog of my alcohol and drug addiction, I somehow acknowledged that subjecting my body to that kind of stress would be…