Actor Chris Hemsworth says he is taking a break from acting after learning he has a heightened risk of developing Alzheimer’s disease.

The Thor star made the discovery after undergoing tests as part of his Disney+ documentary series Limitless.

He told Vanity Fair the tests confirmed his “biggest fear”, adding he will now be trying to take “preventative steps”.

Alzheimer’s is the most common form of dementia and can cause memory problems, confusion and communication issues.

Hemsworth learned that he has two copies of the gene ApoE4, one from his mother and one from his father, making him between eight and 10 times more likely to develop the disease than those without both copies of the gene.

About 2 to 3 per cent of the population carries two copies of the gene.

“It’s not like I’ve been handed my resignation,” Hemsworth said, but added the news “really triggered something in me to want to take some time off”.

“If you look at Alzheimer’s prevention, the benefit of preventative steps is that it affects the rest of your life,” he said.

“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.”

The Limitless series sees Hemsworth test his body and explore ways to live longer and healthier.

He explained that he had not been diagnosed with Alzheimer’s disease, but had been warned of the heightened risk. “It’s not a pre-deterministic gene, but it is a strong indication,” he said. “Ten years ago, I think it was more thought of as determinant.”

Hemsworth said the original plan for the series would have seen him receive all his genetic test results live to camera – but series creator Darren Aronofsky told him privately once they got the results.

The Marvel star was subsequently given the option of removing any references to Alzheimer’s from the show, but decided to include his genetic risk of Alzheimer’s to improve awareness and understanding.

“My concern was I just didn’t want to manipulate it and over-dramatise it, and make it into some sort of hokey grab at empathy or whatever for entertainment,” he said.

Hemsworth also confirmed to the magazine his grandfather has also been diagnosed with Alzheimer’s.

The actor will soon be seen in George Miller’s forthcoming Mad Max sequel Furiosa, which concluded filming earlier this month.

The 39-year-old said he would take a break from acting after finishing the publicity tour for Limitless, along with his other contracted work.

He will be going home to Byron Bay in Australia to spend time with his partner, actor Elsa Pataky, and their three children.