"You've got to tell me where you get the motivation to run," he said to me, as he pulled on his gloves and put the collar on his dog, a Springer Spaniel, I think. The sun was on the verge of setting, and I was at the midpoint of my 7-mile run, in a neighborhood somewhere. It was unfamiliar territory, and the bike path was hardly cleared of snow, but it was a good run, despite the cold temperature.

I don't know the man, but I hit "pause" on my iPod, and slowed to make small talk.

Where do I get the motivation? he wondered.

Good question. It was nearing 5:30, and dark, on a Sunday night. My only fuel, this time around, was a peanut butter sandwich and leftover tears from an earlier argument. My eyes still burned.

If you'd have asked me at noon, while I was still in bed, wrapped in blankets, if I planned to get up and run for over an hour, outside, the answer would've began with "hell" and ended with "no."

So I didn't know what prompted me. A bad day, perhaps. The need for fresh air, a new route, a spin of the new iPod playlist, which was fantastic, by the way. But I didn't tell him that.

I don't know that I know what motivates me. It's certainly different each day. Most times it's a plan. The schedule is telling me to run six miles today, or I promised myself I'd get on the treadmill tonight.

Other times it's a fear of failure or unpreparedness. If I don't get in the mileage, I won't be ready. I'll never hit an an hour and 45 minutes, or my 5K will never improve. Another marathon will kill me.

This is hardly something worth admitting, but other times it's to burn the calories. The previous night's four slices of pizza, or the afternoon's chocolate chip cookies need to go somewhere other than my ass.

Good girl time is another, when I've got someone to run with. Someone who'll listen. Or someone who'll just talk, and let me listen. Between work and sitting at home with a book in my lap or watching Jeremy play video games, a few miles with a girl friend is the little socialization I get.

But most of the time it's just for me. My own completely selfish act. I need out of the house. I need fresh air. I need to sweat, to clear my head. It's therapy, however cliche. It's Me Time. No one can interfere.

I do it for the feeling of finishing. The burn in my legs and in my lungs. Because it feels so good to stretch my muscles afterward, and to feel my heart beat. I run because I can improve, and because I'm healthier for doing it.

I run, like I've said so many times, because I can. But that's not what I told him.

"You know, I have no idea," I said, as he turned to walk his dog and I hit "play."

"Well, that's awesome," he called after me. "Good for you."

Good for me, indeed.