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