Discover the secrets for super endurance -- from one of the fittest men on the planet! Dean Karnazes has run 350 continuous miles through three sleepless nights

The ultrarunning legend takes on the ultimate test of endurance: running 50 marathons in 50 days.

The ultrarunning legend takes on the ultimate test of endurance: running 50 marathons in 50 days.

In the fall of 2006, Dean Karnazes, known as the "Lance Armstrong of the running world," took on the ultimate challenge: running 50 marathons in 50 states in 50

Ultrarunning legend Dean Karnazes has run 262 miles - the equivalent of ten marathons - without rest. He has run over mountains, across Death Valley, to the Sou