People go on 5K and 10K runs all the time. But what's the farthest humans can run at one time? When you purchase through links on our site, we may earn an affiliate commission. Here’s how it works.

From muscle fibers to mental grit, here’s the science behind why some bodies can endure ultramarathons, while others hit the wall far sooner. Ultramarathons sit at the far edge of what the human body ...