The ultramarathon legend who ran 350 miles nonstop says the key to doing hard things is simpler than most people think

Courtesy of Dean Karnazes Dean Karnazes holds the world record for the longest distance a human has ever run nonstop. His advice for going farther than you think you can: redefine success before the race begins. When the pain hits, Karnazes says there’s one rule: keep moving — even if you have to walk. For decades, scientists have tried to understand what separates people capable of extraordinary endurance from everyone else. Is it genetics? VO₂ max? Pain tolerance? Mental toughness? Dean Karnazes has spent more than 30 years giving them a remarkable case study. He's run 50 marathons in 50 states in 50 consecutive days, crossed Death Valley in the middle of summer , and in 2005 set the record for the longest nonstop run — covering 350 miles in 80 hours and 44 minutes. Even that wasn't enough.