To uncover the secrets of longevity, Chris Hemsworth put his body on the line

Chris Hemsworth plunged into Arctic waters, dangled a thousand feet over a canyon while climbing a rope, fasted for four days, and prepared for his own eventual death—all in the pursuit of living longer.

In Limitless With Chris Hemsworth, a six-part National Geographic documentary streaming on Disney+, the actor doesn’t just rely on a physique honed during a decade of playing Thor in movies. He challenges mind as well as body in a quest to develop habits that might extend life. His, and ours.

Experts guide him. Some of their tips sound familiar—eat less, exercise more—but others, less so: Accept reality. Harness stress. (What wild baboons can teach us about aging)

Before this project, Hemsworth had “always trained specifically for a movie,” where the goal might have been “to have abs this summer or whatever. And it was more superficial. I always felt better, but doing a deep dive into the science-backed evidence of why I felt better was a completely new experience,” the actor tells me, from his Byron Bay, Australia, home. 

Limitless—which took more than two years to complete, given pandemic shutdowns and breaks for Hemsworth’s movies—stemmed from a 2006 film that producers Darren Aronofsky and Ari Handel had written: The Fountain, about a man searching for everlasting youth. Handel recalls a line that resonates today: “Death is a disease, it’s like any other. And there’s a cure. A cure—and I will find it.”

Nearly two decades ago, they worried the idea was implausible for audiences. Now, with an aging population and high-tech companies “trying to beat death and reaching for immortality in a lot of different ways,” Aronofsky says, it doesn’t seem as far-fetched.

With production company Nutopia, the team set out to craft a series about longevity that was informative yet entertaining. Hemsworth undertakes complicated stunts, but there are takeaways for viewers at home. Nutopia executive producer Jane Root says it’s less a sci-fi vision of extending life and more about improving chances for a long “life that is fulfilled and happy and active.” 

How active? In Norway, to study extreme temperature’s effects on the body, Limitless had Hemsworth swim and surf in a fjord’s 36-degree water. Aronofsky—who managed a numbing dip himself—said it was “an amazing experience to … see Chris really pushing himself to the edge.”

To push that hard takes exceptional drive, says Ross Edgley, who coached Hemsworth’s fjord swim. A sports scientist and the only person to swim around Great Britain (some 1,790 miles), Edgley also helped him train for the movie Thor: Love and Thunder. “People know Chris as the actor, but not a lot of people know him as the athlete,” he says. Hemsworth had been a hurdler in his school days and still surfs. (Athletes are going faster, higher, and farther—thanks to technology and smarts)

In Limitless, Hemsworth plays underwater hockey during a four-day fast, part of a test to measure fasting’s potential benefits. The actor tends to keep the mood light, joking about being hungry. But there’s a dark moment when Peter Attia, a preventative care physician, tells Hemsworth, then 37, that blood tests reveal he has 10 times the average risk of developing Alzheimer’s disease because of genetic traits. Daily exercise, good sleep, and stress reduction might help lower that vulnerability, Attia adds. 

“It was initially pretty scary,” Hemsworth says. “But now, because of this information, there’s an opportunity to live an even better life.”

Hemsworth’s extreme feats in the series include walking on a two-foot-wide construction beam 900 feet above Sydney Harbor. And yet it’s simple scenes in the finale—an episode about accepting reality and death—that crystallize why we yearn to live longer.

Wearing an MIT-designed suit that replicates aging by limiting movement and dulling the senses, Hemsworth spent three days in a retirement community. Listening to people whose deaths were imminent, he said, was a lesson “in many ways of health and wellness but, most importantly, in how to live a beautiful life.”

Photograph by Craig Parry, NATIONAL GEOGRAPHIC FOR DISNEY+

For a few moments at a time, Hemsworth experiences aspects of old age. He wears an MIT-designed suit that adds weight and restricts movement, hearing, and vision, mimicking how he might feel in his late 80s. He listens to people who are close to death and reflects on what matters. He’s then led toward an apparently older woman, sitting with her back to him—and the second he touches her shoulder he recognizes his wife, Elsa Pataky, under extensive aging makeup. She turns to him, and they embrace.

The show team hadn’t warned Hemsworth about this encounter; they wanted his purely natural reaction. Suddenly, he’s trying to reckon with being near the end of his days, and it’s evident why he’ll sweat, freeze, and starve. Does it all come down to love?

“Absolutely,” Hemsworth says, a smile creasing his face. “One of the first questions I had from Peter Attia was, What does your life look like in 20 years … in 30? What does your death look like?”

Hemsworth pauses. Then he says, “A good death for me would be having lived a good life.”