Dean Karzanes can run 350 miles without stopping. The 53-year-old marathon runner has no trouble running a marathon. He even does them back-to-back with hardly breaking a sweat. His endurance is credited to his body's ability to flush lactic acid from his system. "I don't care how fast I go," he told IE. "I care about how far I go." He sets out at 2 a.m. to run his first 26.2-mile jaunt. When he finishes, he joins another 5,000 runners for a marathon in Monterey, California.