NatGeo's 'Limitless With Chris Hemsworth' pushes the star to his physical, mental limit

NEW YORK CITY -- As Thor, Chris Hemsworth became one of the world's biggest stars and one of the most physically fit, but a new series from National Geographic streaming on Disney+ puts the actor to the test like never before.

"Limitless" is designed to show us mere mortals how to live better and longer by placing Hemsworth in extreme situations.

"I'm outside of my comfort zone more than I've ever been," Hemsworth said in the trailer for the new series.

Hemsworth said challenges in half a dozen episodes led him to think, "I've lost my mind."

He took a swim in the Arctic, walked across a narrow crane stretched out from a skyscraper, and climbed up a rope below a cable car 1,000 feet above mountains.

At the premiere of the series at Columbus Circle in New York City, Hemsworth told Eyewitness News Entertainment Reporter Sandy Kenyon filming the series often felt like he was actually defying death.

"There are all sorts of doubts and demons in my mind saying I couldn't do it and what if I don't?" Hemsworth said. "And, thankfully, had Ross Edgley there saying, 'this is possible.'"

However, Edgley said at the time of the rope climb, he thought, "this is a terrible idea. I was so nervous."

Now that everyone is back on safe ground, the coach can say that "Limitless" is great TV. It is also intended to help us.

"I think Chris' purpose isn't to be an example, it's more to get people to shift their barometer of what they think is possible," Edgley said. "Even if people look at that and see him swimming across an Arctic fjord and they say 'OK I'm not going to do that, but maybe after my morning shower, I can turn the tap on cold for 30 seconds."

There are health benefits to be found by watching these extreme situations, according to health experts that were a part of the project.

"In my episode, I focus on stress," Dr. Modupe Akinola said.

She wants viewers to ask, "how can I make sure to use my body, my physiology to breath in a way that will help me in stressful situations?" And, then she demonstrated some techniques.

"Limitless" has already helped its star, who admitted he's had a "fight or flight" approach to life built on adrenaline.

"It got me to this point but realizing how detrimental that is to our health," Hemsworth said. "It's not about not working hard and committing to something, but it's also making sure you take pause and take time for yourself just to be still and simplify things, and I've definitely incorporated that more than I have in the past."

"Limitless" is streaming right now on Disney+, which is owned by the same parent company as this station.