While filming his National Geographic docuseries, Limitless, the actor, 39, learned he had a greater-than-average chance of developing Alzheimer’s after finding out he has two copies of the gene APOE4, which is linked to an increased risk of the neurodegenerative disease.
“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,” Hemsworth told Vanity Fair of the fourth episode, entitled “Memory,” in which a doctor tested him and told him the news on camera.

Upon hearing the news, the Thor star said he had a hard time navigating what to do with the information.
According to a 2022 Stanford-led study, “about 25% of people with European ancestry have one copy of APOE4, which more than doubles their chances of developing late-onset Alzheimer’s. Another 2% to 3% of people have two copies of the variant, which renders them 8 to 10 times more likely to get the disease.”
Hemsworth says his grandfather is currently living with the disease. While he hasn’t seen him in a few years, he’s relied on family members to provide updates on his health.
At one point, Hemsworth says the doctor who gave him the test was concerned about delivering his results on camera. The actor was even “offered a version of the episode where we didn’t talk about it,” but after considering how it may help others, he decided to approve the scene.
“My concern [with the episode] was I just didn’t want to manipulate it and overdramatize it, and make it into some sort of hokey grab at empathy or whatever for entertainment,” Hemsworth said.
“If this is a motivator for people to take better care of themselves and also understand that there are steps you can take, then fantastic,” he added. “If you look at Alzheimer’s prevention, the benefit of preventative steps is that it affects the rest of your life. 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.”
Still, while the news came as a shock, Hemsworth says it’s only motivated him to live life to the fullest.