‘Super-Human’ Marathon Runner Dean Karnazes Can Jog 350 MILES Without Stopping, But Compared To This Tribe’s Record …

• Dean Karnazes has never had a cramp despite running hundreds of miles
• The 53-year-old has a rare condition which allows his body to rapidly flush lactic acid from his system – before it builds up in his muscles
• It’s allowed him to compete in the toughest endurance races in the world
• He has completed fifty marathons in fifty states in fifty states in 2006
• Karnazes also ran a marathon to the South Pole in temperatures of -13F
• He sprinted 350 miles in just 80 hours and 44 minutes without sleep

He has run a marathon to the South Pole in temperatures of ?13 °F, completed fifty marathons in fifty days – one in every state – and most famously sprinted 350 miles in just 80 hours and 44 minutes without sleep.

Yet unstoppable marathon runner has never had a cramp or even experienced his muscles seizing up.

Now Dean Karnazes has revealed that his superhuman abilities are down to a quirk of his physiology. The 53-year-old has a rare condition which allows his body to rapidly flush lactic acid from his system.

Typically, as we exercise, the body converts glucose to energy which produces lactic acid as a by-product. As that builds up in the muscles, it begins causing cramps and fatigue as a signal to stop.

Karnazes never receives those signals. As a result, he is able to keep on running without stopping and compete in some of the toughest endurance races in the world.

‘At a certain level of intensity, I do feel like I can go a long way without tiring,’ he told the Guardian previously.’No matter how hard I push, my muscles never seize up. That’s kind of a nice thing if I plan to run a long way.’

During one incredible feat, he was able to keep running for three days and three nights without sleep – although he admits that the third night took all his willpower.