On Sunday, more than 50,000 athletes are expected to compete in the New York City Marathon, one of the largest, and most elite marathons in the world. Running a continuous 26.2 miles is a major physical challenge. But what exactly is happening in the body when running such a long distance?

Joining guest host Rachel Feltman to answer questions from long-distance runners is Dr. Brandee Waite, Director of UC Davis Health Sports Medicine. Over the past 20 years, Dr. Waite has directed the medical care for multiple marathons and ultra-marathons, and has served as a team physician for USA Track & Field.

Transcript for this segment will be available after the show airs on sciencefriday.com.

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