The man who can run forever

Dean Karnazes (right) during an ultra marathon race in California in July. -- AFP/ Getty Images/David McNew

Dean Karnazes can run for three days and three nights without stopping. What’s his secret?

FROM club runners to Olympians, every athlete has a limit. Scientifically, this limit is defined as the body’s lactate threshold and when you exercise beyond it, running rapidly becomes unpleasant. We’ve all experienced that burning feeling – heart pounding, lungs gasping for air – when your muscles begin to fatigue, eventually locking up altogether as your body shuts down.