When actor Chris Hemsworth, who played Thor in the Marvel series, agreed to participate in a longevity documentary a few years ago, he decided he would learn how to live better so he could live longer. But he never expected to learn something that could significantly impact what those future years might look like.
In the documentary series Limitlessreleased in 2022 by the company National GeographicHemsworth took a series of tests to find out what he could do to extend his healthy years. However, a genetic test showed that he has two copies of the Alzheimer's risk gene. Although genes do not guarantee that one will develop the neurodegenerative disease, carriers have an 8-10 times higher risk.
The diagnosis was not a complete surprise; Hemsworth's grandfather had the condition, and his father Craig also lives with it. While Hemsworth is not showing any symptoms yet, his father is showing early signs of memory loss. In the new National Geographic documentary film called A trip to rememberhe and his father are studying the growing science of potential treatments for brain diseases and how research shows they can slow their progression. The hope is that this will help people at higher risk stay healthy and resilient for as long as possible.
After learning of his genetic risk, Hemsworth made changes to his life, slowing down his acting career to prioritize time with family, and also took steps to keep his body and mind healthy. Talking about his high-risk status is part of his reaction to life-changing news; in 2022 Vanity Fair interviewHe said: “If it motivates people to take better care of themselves and also realize there are steps you can take, then that's fantastic.”
In the latest film, Hemsworth focuses on an aspect of Alzheimer's treatment that usually doesn't get attention: the role that diet, exercise, sleep and staying socially active can play in the progression of the disease. developing research shows that improved nutrition, I train moreI sleep well stress reductionand staying socially active may slow the risk of developing later stages of Alzheimer's disease. In an effort to help his father, Hemsworth focuses on social connections and goes on a trip with his father to their former home in the Australian outback. There, he helps his father reunite with old friends and remember, hoping that the memories will not fade.
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The idea for the literal and figurative trip down memory lane came from Suraj Samtani, a psychologist and research fellow at the University of New South Wales Center for Healthy Aging Brains, who served as the film's scientific advisor. Samtani studies what is known as social frailty, or the extent to which a lack of social interactions can affect the progression of their disease. This is not a new concept, but it is gaining traction in the medical community as a potentially important factor in reducing the risk of Alzheimer's disease as early as possible in the disease's stages. Combining strategies that involve maintaining or building social connections with Alzheimer's drugs could be an important way for people like Hemsworth and his father to stay mentally alert longer.
“We knew from previous studies that loneliness was as bad for brain health as smoking 15 cigarettes a day,” Samtani told TIME. “And that social connections are the most important factor in delaying the onset of many chronic diseases. But we wanted to know: What is the recipe for brain health through social connections? And do social connections still matter after you account for all the other known risk factors for dementia?”
Samtani dived into Sydney Study of Memory and Agingwhich includes data on more than 1,300 people, some of whom underwent brain scans, blood tests or cognitive tests over a 14-year period. Participants also provided information about their diet, social connections, and other lifestyle factors. Samtani and his colleagues recorded the number of cases of dementia, including Alzheimer's disease, the most common form, in the group.
“We found that social connections are incredibly protective,” he says of the results he and his colleagues found. published in 2022. “People with good social connections had half the risk of developing dementia than everyone else,” says Samtani. “It shocked us. We knew it was important, but we didn't expect it to be such a powerful protective factor.” Social activity seemed to “inhibit cognitive decline,” he says, in people who had already begun to experience cognitive problems.
A year later they reported that people with stronger social connections not only have a lower risk of developing dementia, but also have lower overall mortality from any cause compared to people with weaker social connections.
Samtani is now working with an artificial intelligence bot to simulate the impact that social connections and conversations can have on people with Alzheimer's disease, especially those who may be increasingly isolated and lack a strong network of friends or family. The bots, called Viv and Friends, connect with people on iPads and are designed to have conversations specifically designed to stimulate memories for people with dementia. He plans to publish the results of the first small study involving 12 older people living in a residential care home without regular visitors. “Viv is designed to talk to people about a variety of topics, to stimulate the mind, and also to provide people with emotional support when they feel upset,” he says. Although they are still analyzing the results, he says one resident who spoke to Viv over five weeks reported that they were the longest conversations she had had in a long time. “The idea is to replace the loneliness that people may feel and provide them with cognitive stimulation instead,” Samtani says.
Why Social Connection Benefits the Brain
According to Samtani, there are several key features of good social connections. The quality of these relationships matters more than the quantity: people can have a large network of social connections but still feel lonely if they do not receive adequate emotional support.
In his research, Samtani also identified two factors that seem to distinguish people with good interaction quality. One had connections with people outside of friends and family and outside the home. This is because your brain doesn't have to work as hard when interacting with the people you live with. “You're talking about a variety of topics” that “stimulates the brain and leads to cognitive reserve, or how much potential the brain has to continue to function. Sometimes that cognitive reserve can protect against Alzheimer's disease.”
The second feature of strong interactions is whether a person has someone they can trust and lean on during stressful times. Stress can increase inflammation, especially in the brain, which can be detrimental and contribute to the development of Alzheimer's disease.
One way to build these connections is through reminiscence therapy, or reactivation of memories from the past. Looking through photo albums and reliving events with family or friends can keep memory circuits active and help maintain cognitive reserve.
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That's the approach Hemsworth takes with his father as they return to Bullman in Australia's Northern Territory, the remote town where the family lived when Hemsworth and his brothers were young. “I know that for my father’s cognitive health, returning to Bullman must be powerful therapy,” Hemsworth says in the film. There, in the rural outback, Craig helped fight with buffaloes, barely dodging their horns, and for his fearlessness he received the nickname “Chuck Norris” in society.
Reactivating old memories forces the brain to train itself to revive feelings, smells, sounds and more, Samtani says, and this process can keep these circuits active and hopefully protect them from more rapid decline.
Back in Bullman, Craig and Chris reunite with old friends, and as the memories come flooding back, Craig becomes more animated and interested. Chris notices that his father is becoming more present, although he still experiences brief moments of confusion when he begins to talk to an old friend. Samtani says a sense of belonging, trust and love are some of the reasons why social connections may help fight neurodegeneration caused by Alzheimer's disease.
In the film, Hemsworth says that returning to Bullman is like putting together “pieces of a puzzle.” “I think my dad had a greater sense of involvement,” he says of his return to their former home. “By the end of the trip he felt much more comfortable and open than at the beginning. Something was ignited there.”
“It’s reminiscence therapy at an enhanced level combined with the power of social connections,” Samtani says in the film.
Reawakening old memories and strengthening social connections may be just one potential way to combat Alzheimer's disease, highlighting the possibility of intervening early in the disease to hopefully slow its relentless progression.
After a trip with his father, Hemsworth notes one of the great paradoxes of Alzheimer's disease: the disease gradually strips people of the social connections and bridges people build with others, but those same networks are important tools for combating that decline. This awareness could help more people like his father, who is in the early stages of the disease, or even those like Hemsworth himself, who is at high risk but not yet showing symptoms, be better prepared to withstand the brain changes that could otherwise be so devastating.
