NEW YORK — Chris Hemsworth's new show with National Geographic on Disney Plus is "a mission to live better for longer." But because of that show, he has come face-to-face with his "biggest fear" – that he might develop Alzheimer's disease.
During one episode of the show, the 39-year-old "Thor" actor underwent genetic testing to learn more about his present and future health. It turns out that Hemsworth has a rare genetic makeup with two copies of the APO4 gene, which has been connected to an increased risk of Alzheimer's disease.
"ApoE4 is the strongest risk factor gene for Alzheimer's disease," a 2021 study by the National Institutes of Health says, "although inheriting ApoE4 does not mean a person will definitely develop the disease."
While about 25% of the population has one copy of the gene, only 2% to 3% have two, according to that research.
"The idea that I won't be able to remember the life I've experienced or my wife, my kids, this is probably my biggest fear," Hemsworth says in the show's fifth episode.
During filming, the show's longevity doctor Peter Attia first told Hemsworth about the finding off-camera, Hemsworth told Vanity Fair. That conversation, Hemsworth said, "was pretty shocking."
"It was a pretty brief conversation, all things considered. I hung up the phone and my parents were there, at the time," he told Vanity Fair. "...I told them, and then they had a bunch of questions. I had a bunch of questions, but no one answered them. I wish I'd had a more intense follow-up with it because I didn't really know what to think. I was like, 'Am I supposed to be worried? Is this concerning?'"
Attia told Hemsworth in the episode that he is about 8 to 10 times more likely than the general population of developing Alzheimer's. According to the National Institutes of Health, it's also associated with early onset, which can happen anytime between someone's 30s and mid-60s.
"There was an intensity to navigating it. Most of us, we like to avoid speaking about death in the hope that we'll somehow avoid it. We all have this belief that we'll figure it out," Hemsworth reflected to Vanity Fair. "Then to all of a sudden be told some big indicators are actually pointing to this as the route which is going to happen, the reality of it sinks in. Your own mortality."
It's also a disease that his family has significant experience with. Hemsworth's grandfather has Alzheimer's.
"He doesn't remember who we are, you know his grandkids, but also his own children he forgets. It's heartbreaking," he says in the show.
He also told Vanity Fair that there are some days when his grandfather is "quite joyful and gives you a big hug."
"I'm not sure he actually remembers much anymore and he slips in and out of Dutch, which is his original language, so he'll be talking Dutch and English and then a mash-up and them maybe some other new words as well," he said.
Despite his genetic makeup and family history, Attia told Hemsworth, "it's my belief that if we take every step possible, we can reduce your risk to that of anyone else."
The finding propelled Hemsworth to take action. According to the National Institute of Aging, physical activity, blood pressure control and cognitive training – activities that help enhance memory, reasoning and processing speed – could help ward off the disease's onset, although those findings are inconclusive.
"It's not like I've been handed my resignation," he told Vanity Fair.
"When you have preposition to cardiovascular heart disease, cancer, anything—it's all about sleep management, stress management, nutrition, movement, fitness. It's all kind of the same tools that need to be applied in a consistent way," he said
But at the end of the day, Hemsworth told Vanity Fair that what matters most is making the most out of life for as long as you can.
"Whether or not any of this information helps you live longer, it's about living better right now," he said. "Whatever you do right now to benefit your future self is having a huge benefit in your current self. ... Live with as big a sense of gratitude and love for life as you can."