At 64, Chinese rehabilitation expert Dr. Li Jian'an was overweight, suffered from severe fatty liver disease and struggled to walk 500 meters. A decade later, he has completed 140 marathons, using his own body as a living case study in healthy aging. But his transformation has also come with challenges. 

His wife of over 40 years worries about his safety and the loss of family time, even as she supports his determination. Meanwhile, fellow sports medicine experts point out that extreme running isn't a one-size-fits-all solution.

For Dr. Li, running offers quietude for inner reflection. From starting at 64 to setting his sights on 100 while continuing to run, Dr. Li remains committed to finding a balance between personal ambition, family and scientific approaches to fitness.

Executive Producer: Zhang Jingwen
Producer: Yang Sha
Directors: Chen Hongyu, Zhong Xia, Zong Shukang
Video Editor: Zhong Xia
Copy Editors: Denique Daniels, Zara Poghosyan, Gift Mona, Yang Sha
Narrator: John Goodrich
Videographers: Gao Shengwei, Chen Jiazheng
Cover Image Designer: Sha Yunjin