Dharam Pal Singh, a champion marathon runner from rural India, is 119 years old. At least that’s the age he claims to be. He refers to his passport, voter ID card, and tax-identification card—all government-issued identity documents—to prove his date of birth, which all of the documents list as 1897. But he lacks a birth certificate, likely due to the fact that they were not regularly issued in remote villages in India at the time of Singh’s birth.

The controversy around Singh’s age has become something of an international media sensation. “If Dharam is as old as he says he is, that would make him the oldest man alive—as far as we know,” the filmmaker David Freid told me. “And if Dharam is the oldest man alive, and running marathons, I'd like to know his secret, and I think others would too.”

Freid’s documentary The Never-Ending Marathon of Mr. Dharam Singh explores that very question. The filmmaker traveled to India and Nepal to interview Singh and his proud supporters, some of whom have been medically treating the runner for decades with various homeopathic and spiritual remedies. Singh practices yoga and meditation. He says in the film that his daily diet consists of “a concoction that I make from leaves from various plants and trees,” which he forages in order to make a vegetarian chutney. He believes his healthy lifestyle enables him to continue his international athletic exploits.

In the film, Freid also tracks down Singh’s skeptics, including an expert in adult-age-group track-and-field competitions, who maintains that he has never heard of a runner over the age of 110 who has successfully completed a marathon event.

Freid himself believes that the skepticism will persist until Singh can produce a birth certificate. He also notes that Singh is not the first elderly Indian runner to be refused recognition for this very reason. But in the end, Freid said, “the goal wasn't to expose Dharam as a fraud. Nor was it to prove his birthday. The door is open for the viewer to decide.”

“When we confronted him about the findings of various interested parties, he shrugged it all off enthusiastically,” Freid continued. “Whether he was or not, Dharam believes he was born in 1897.”

“I am running to bring pride to India,” Singh says in the film. “I run in the streets of the village and the kids run along with me. As long as I’m alive, I will keep running. I’ll run until I die.”