What was it like to run 20 miles?

Four weeks into my 16 week marathon training for Boston, I ran my first 20 mile run this past Saturday.
I think running 20 miles in 20 degrees with strong head winds wore on me physically and mentally. My face was frozen and legs were tired after 16 miles. I had to have positive mental thoughts expressed verbally in order to finish the run. I began to think what happens to you mentally when you're involved in a long run. I'm sure there are more writings to define the effects of mental stress from endurance activities but I like this little article I found online at Mens Health

Behind the Science - Does running by yourself hurt your brain?
Edited by: David Schipper
The study: Research at Princeton University suggests that exercising alone hinders neurogenesis, the creation of new brain cells. Rats that lived alone and exercised alone showed a loss of brain cells; those that lived and exercised in a group showed an increase. Researchers speculate that having a partner blunts the cell die-off that typically occurs when the brain reacts to the stress of exercise.

A closer look: It was a rat experiment, and the lonely rodent runners had to live alone, too. "Running is not at fault here, but the living in isolation that can cause the brain to deteriorate is," says Charles Hillman, Ph.D., a professor of kinesiology at the University of Illinois who has studied the effects of exercise on the human brain. When Hillman measured cognitive function in men who had exercised in isolation for 30 minutes, he found improvements in their brain function. "It's a definite sign that your neurogenesis is not being negatively affected," he says.

Our advice: Run alone or with somebody. Either way, it's smart.

OK, but my spirits did get a little pick-up when someone driving by gave me a friendly wave and toot from the horn. And when another lone runner, coming from the opposite direction, said words of encouragement for running early in the morning cold. At that point I realized I need someone to run long with. I feel much better when there is someone else I can share the pain with. But if I have to go at it alone, maybe it'll make me tougher and that my neurogenesis will not be negatively affected, I should be OK.