"These days he runs 70 to 120 miles a week and regularly runs all night, sometimes putting the kids to bed on a Friday night, setting out for a hot spring 70 miles from home and meeting the family there in the morning."

What's scarier is that he's not "just" an ultramarathon runner. He surfs, swims, and bikes ridiculous distances too. From his site:

On one occasion, Karnazes ran 100 miles all-night to the start of the Napa Valley Marathon, and then completed the marathon in 3:15.