Fortune: When I turn my brain loose, will it always find its way home?

COLUMN

A few weeks ago, after a long run, I walked up to the passenger side of my car, opened the door and then stared for several seconds at the completely unfamiliar contents of the vehicle.

I stood gaping stupidly for several seconds, trying to figure out who had placed these strange things in my Honda, before a man spoke to me from where he stood on the driver's side. "This isn't your car," he said. "Your car is down there."

He pointed to other side of the lot, where my car - the same make and color of the one I had just opened - sat waiting. I stammered an apology and tried to explain.

"I'm really sorry. I'm in a trance," I said. "It happens when I run."

I have a hectic, noisy life. I have a busy job, I teach a writing class, I have two young sons and a wonderfully complex network of family and friends. I am rarely alone and virtually never idle. Most of the time I love all the commotion. But I also need to run.

And when I run, I do a little trick I call letting my brain off-leash. I untether mentally from what I'm doing, from where I am, even from who I am, and I just run.

The first couple of miles are typically kind of unfun. They're the miles when my brain is still churning through all the detritus of the day, sorting and prioritizing and digesting and overanalyzing. But something happens at about mile three. Somewhere in there, my brain goes off-leash.

One side effect of this is that I can't run in the city. Every day, I see people jogging in place at intersections, waiting for the light to turn, navigating traffic and gauging the gaps between vehicles. I'm simply not capable of that level of calculation when my brain is off-leash.

Friends sometimes tell me they've seen me out running - that they said hi but I didn't seem to hear or see them. And I didn't. If you woke me from a dead sleep at 2 a.m., I'd be more capable of a coherent conversation than if you tried to talk to me at mile five of a run. I won't stop. I won't see you. I'm not there.

Sometimes, around mile seven, I even have floaty, out-of-body experiences. I can watch the dark top of my ponytailed head - I can see the shot of gray that is colonizing my right temple at a discouraging rate. I can observe my scrawny, swaying shoulders. It's fascinating.

My skeptical (nonrunning) friends tease me that this is a clear sign I've run a little too far. They laugh at me when I tell them it's actually a tremendously pleasant experience.

"Yeah, I love dehydration and hallucinations," they giggle. "Nothing like a near-death experience to make the evening interesting."

I know, of course, that this is not a new phenomenon. In fact, The New York Times recently ran an article about what causes the much-researched "runner's high" that I'm presumably experiencing. Endorphins were the old theory. The new theory is that our bodies produce endocannabinoids (yes, like in cannabis) after long periods of strenuous exercise.

Honestly, I don't know why it happens. And I don't care. I just know I have to be careful to only run where I won't encounter traffic. And that I really need to wait for my brain to get back on-leash before I go around opening car doors.

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