For a new series on longevity,actor Chris Hemsworth tests both accepted and extreme ?strategies for enhancing health.

Chris Hemsworth plunged into Arctic waters,dangled high above a canyon while climbing a rope, fasted for four dats,and prepared fir his own eventual death-all in the pursuit of living longer.

In Limitiless 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 hi,.Some of their tips sound familiar-eat less,exercise more-but others,not so much: Accept reality. Harness stress.

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 Hemswoirth's movies-stem from a 2006 film that executive producers Darren Aronofsky and Ari Handel had written: The Fountain ,about a man searching for exerlasting youth. Handel recalls a quote 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 compony 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 om 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 pus that hard takes exceptional drive, says Ross Edgley, who coached Hemsworth for his fjord feat.A sports scientist and the only person to swim around Great Britain(some 1790 miles), Edgly also helped himtrain for the movie Thor:Love and Thinder. "People know Chris as the actor, but not a lot of people know him as the athlete," heSays.Hemsworth had been a hurdler in his school dats and still ?surfs.

In Limitless,Hemsworth plays underwater hockey during a four-day fast, pat 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 rebeal 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,threr's an oppotunity to live an even better life."

Hemsworth's extreme exploits inthe series include walking on a twi-foot-wide construction beam900 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.

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 feelin his late 80s. Helistens 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 se touches her shoulder he recognizes his wife,Elsa Pataky,under extensive aging makeup. She turns to him, and they embrace.

The show's team hadn't warned Hemsworth about this encounter; it 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 foe me would be having lived a good life."