Ultramarathoner pushes limits of human body

Dean Karnazes, who has been running his entire life, decided to push the limits and see how far he could run. He started out with a non-stop 30 mile run. When he survived that, he tried 100 miles, then 135, and then 199 miles. As if that wasn't enough, he ran 262 miles last summer, NON-STOP! I went through conditioning for baseball this year, and I thought I was going do die after some of our runs, a few of which were well over 5 miles. I can't imagine running 30 miles non-stop, let along 262. Although this link appeared on CNN's homepage, I still find myself a bit skeptical. Any thoughts?