Think one marathon is tough? Try 50, in 50 states, on 50 consecutive days. Dean Karnazes has. He’s also run 350 miles in 82 straight hours, raced in 120-degree heat and in below-zero temperatures and thinks 31 miles counts as a short race. At 49, Karnazes is the ultra, ultra-marathoner and, surprisingly, also kind of a softy — proud of anyone who laces up their sneakers, gets out there and runs.

Think one marathon is tough? Try 50, in 50 states, on 50 consecutive days. Dean Karnazes has. He’s also run 350 miles in 82 straight hours, raced in 120-degree heat and in below-zero temperatures and thinks 31 miles counts as a short race. At 49, Karnazes is the ultra, ultra-marathoner and, surprisingly, also kind of a softy — proud of anyone who laces up their sneakers, gets out there and runs.