Learn more about the impact ultramarathon running has on red blood cells and how it may do more harm than good for the body.

Only one runner, Michael Wardian, a 51-year-old from Arlington, Virginia, holds the record for the fastest time accomplishing ...

A study shows ultramarathon running induces oxidative stress and structural damage in red blood cells. Multiomics analyses ...

Distance runner Ashley Paulson of St. George has set a world record in the 100-mile ultramarathon. Friday night, the ...

Camille Herron, 42, is one of the world's top ultramarathon runners, having set 12 world records and becoming the youngest woman to reach 100,000 lifetime running miles. But now, the American athlete ...

Stephanie Case won an ultramarathon race in Wales, running more than 60 miles over rough terrain — and stopping three times to breastfeed her 6-month-old baby, Pepper. In the sport of ultrarunning, ...

You thought the UK was cold when it snowed this winter? Consider how Simon Dicks felt running a five-day Swedish ultra in ...

"I guess I gotta keep going or else it'll probably come back for me," Dean Karnazes told his followers in a video taken just moments after being attacked by a coyote on a 150-mile run Charmaine ...

For the Bull to Bell run, Chiu's toughest stretch was the roughly 30-mile trek along Route 1 in New Jersey from New Brunswick ...