Best known for playing Thor in the Marvel Cinematic Universe, Aussie actor Chris Hemsworth looks like the very picture of health and fitness. Yet as the Avengers star recently learned while shooting Limitless, a National Geographic documentary series on aging and longevity, even superheroes can suffer health scares.

After undergoing a series of genetic tests to probe his own health and future, Hemsworth learned during the fifth episode of the series that he carries two copies of the APOE4 gene—leaving him at a tenfold risk of someday developing Alzheimer's disease.

Taken aback by having his "biggest fear" confirmed, the star now says he's taking an indefinite pause from his career to focus on his family and health. Read on to learn how Hemsworth's discovery changed his life, how you can be tested for a predisposition to Alzheimer's disease, and whether you should.

READ THIS NEXT: Cancer Survivor Rita Wilson Says She Stopped Eating This After Her Diagnosis.

Hemsworth was shocked to learn of his Alzheimer's risk.

It's exceedingly rare to carry two copies of the APOE4 gene, so it came as quite a shock to Hemsworth to learn of his predisposition to Alzheimer's disease. While speaking with Vanity Fair this month, he recalled the moment he learned of his genetic condition. "They took all my bloodwork and did a bunch of tests and the plan was to on-camera tell me all the results and then talk about how you can improve this and that," he recalled. Ultimately, the show creator Darren Aronofsky decided along with the show's health team that the conversation needed to take place off-camera, given the sensitive nature of Hemsworth's results.

"It was pretty shocking because he called me up and he told me," he later told Vanity Fair. "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. 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," he said. "Doing an episode on death and facing your own mortality made me go, 'Oh God, I'm not ready to go yet.'"

READ THIS NEXT: Sharon Osbourne Gives Heartbreaking Update on Ozzy Osbourne's Parkinson's Battle.

He's made major lifestyle changes since learning the news.

The test results left him with more questions than answers, the actor told Vanity Fair. However, he quickly learned that his future was not set in stone, despite his heightened genetic risk. "It was a really good catalyst to dive into everything I needed to be doing in either the prevention front," Hemsworth told the magazine.

"Like everything in the show I went, 'Okay, great. I now have to work on this more,'" the Star Trek star said. "If you look at Alzheimer's prevention, the benefit of preventative steps is that it affects the rest of your life. When you have a predisposition 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."

According to the Centers for Disease Control and Prevention (CDC), you may be able to help prevent Alzheimer's by maintaining a healthy weight, exercising regularly, quitting smoking, limiting alcohol, and managing underlying health conditions such as high blood pressure and high blood sugar.

Not everyone should be tested, experts say.

Hemsworth's high-profile health discovery may leave you wondering whether genetic testing for Alzheimer's is right for you.

"There has been a lot of press coverage around Alzheimer's disease, and around APOE, and it can leave people wondering if they should be tested, if they should be worried, and if they should be making certain life plans," Susan Hahn, MS, CGC, board-certified genetic counselor and Director of Medical Affairs at Quest Diagnostics tells Best Life. However, she notes that "screening for APOE is not considered 'routine,'" and she only recommends it for those with a known family history or the disease, or those presenting with symptoms of Alzheimer's.

For more health news sent directly to your inbox, sign up for our daily newsletter.

Weigh the pros and cons before getting tested.

Hahn says that while direct-to-consumer testing may be available, you should always consult with your doctor or genetic specialist before undergoing genetic testing. "Aside from recommending testing based on guidelines, genetic counselors can help patients navigate the pros and cons of testing, understand their risk, and interpret genetic testing results," she explains.ae0fcc31ae342fd3a1346ebb1f342fcb

Hahn adds that there could be unintended consequences to such testing. "It is difficult to comprehend the stress that accompanies knowing this information. It could also theoretically impact a person's ability to get life and long-term care insurance, as these are not protected by the Genetic Information Non-discrimination Act (GINA). Lastly, people often overlook the impact this will have on relatives. For example, children of those who have two copies of APOE4 are guaranteed to have inherited at least one copy."

As for Hemsworth, he views his own difficult discovery as "a blessing"—one that illustrates the importance of focusing on health and family. Though the actor says he's "not talking about retiring by any means," he's taking some much-needed time to put those cherished things first.

Lauren Gray Lauren Gray is a New York-based writer, editor, and consultant. Read more Filed UnderBrain Health • Celebrities • Health Advice • News Read This Next

• 

  Everything You Need to Know About Ikigai, The New Hygge

  Meet the next "life philosophy" trend sweeping the globe. October 17, 2017
• 

  30 Life Changes You Should Make After 30

  You're too old to skip those doctors visits. February 20, 2018
• 

  This Is Why Lying Is Good for You

  A little fib never hurt anyone—in fact, lying may be good for you. March 26, 2018
• 

  How I Look 15 Years Younger—And How You Can, Too

  The plan is easy, effective, and works for everyone. August 30, 2018
• 

  The Secret to Raising Healthy Kids

  Hint: It's one of the oldest family traditions in the book. December 15, 2017
• 

  40 Genius Ways to Have More Energy After 40

  Revamp your diet, lifestyle, and work habits for more energy—instantly. August 14, 2018
• 

  20 Surprising Reasons Your Hair is Thinning

  Plus proven tricks to get your mane back on track. May 15, 2018
• 

  The 7 Best Luxury Fitness Vacations

  Thinking outside the beach? Try one of these amazing getaways. February 19, 2018
• 

  Is It Possible to Die of a Broken Heart?

  Separating the science from the poetry October 1, 2018
• 

  Here's How Hollywood Director Kevin Smith Lost a Staggering 51 Pounds

  He went from 256 to 205 pounds by following a largely plant-based diet. August 27, 2018