“Go out hard; when it hurts, speed up.”

This is a cool article about a high-altitude distance runner and it's got a bunch of good lines like the one in the title and the two below if you're in need of some inspiration. The dude is sick. I can't imagine running a sub-3 hour marathon at 14kft. In my extremely brief stint of training at high altitude (like 5 runs over 2 weeks in Peru last summer) I was completely messed up by how hard I had to work just to keep moving for 4-6 miles.
During my first run at 3600m (12kft) I had to stop after the first 1.5 miles and sit on the curb and recover for 10 min cause I thought I was going to fall over into traffic. No wonder Kenyans are so fast and Olympians train in Colorado.

“Somebody told me you don’t know who you are until you do a 100-miler,” Carpenter said. “I said, ‘Damned if I’m going to die and not know who I am.’ ”

"Sometimes I lie in bed at night and wonder if I’ve done all I can, and if I haven’t, I go out at night and do more.”

http://www.nytimes.com/2009/02/24/sports/othersports/24runner.html?pagewanted=2&_r=1