CHeBA researcher featured in Chris Hemsworth: A Road Trip to Remember

New research from UNSW’s Centre for Healthy Brain Ageing (CHeBA) is shining a light on the vital role of social connection in protecting the brain from dementia - and now, that message is reaching millions through a new National Geographic documentary featuring Chris Hemsworth, whose father Craig Hemsworth was recently diagnosed with Alzheimer’s disease.

Premiering 24 November 2025 on Disney+, Chris Hemsworth: A Road Trip to Remember explores dementia, memory and healthy ageing through the lens of Hemsworth’s personal journey, as he learns how lifestyle and social factors can slow cognitive decline.

The release coincides with CHeBA’s latest findings, published in The Journals of Gerontology: Series B, which reveal that older adults experiencing social frailty - a lack of social connections, resources and support - are up to 50 per cent more likely to develop dementia.

Led by Dr Annabel Matison and Dr Suraj Samtani, the 12-year study of more than 850 Australians aged 70 and over is the first worldwide to directly compare multiple social frailty indices to determine which best predicts dementia risk.

“Social frailty has been largely overlooked in dementia research,” said Dr Matison. “Our findings suggest it’s not only a key risk factor, but one we can identify early - and potentially change.”

For Dr Suraj Samtani, a Postdoctoral Research Fellow at UNSW’s CHeBA and co-lead author on the study, translating that science to a global audience through the National Geographic documentary has been both surreal and deeply meaningful.

“As a scientist, it’s a dream come true to be part of a National Geographic documentary,” said Dr Samtani. “We’re lucky if a handful of people read our research articles. Having the global reach of Disney and Chris Hemsworth means we can share our dementia research with millions. It’s why I do this work - to help people. Science is not just about research; it’s meant to be shared.”

From the Lab to the Marvel Stadium

Dr Samtani filmed with Hemsworth at Marvel Stadium in Melbourne, where the two discussed the importance of mental wellbeing and social connection.

“Chris is incredibly down-to-earth,” said Dr Samtani. “But what stayed with me was his sincerity. He genuinely wants to promote healthy ageing and reduce stigma around dementia.”

“When we spoke about his father and his own future, he was open and vulnerable. Seeing that side of him was inspiring. I hope it encourages men to talk more about their feelings and helps families speak more openly about dementia.”

In another moving moment, the production team recreated Hemsworth’s childhood home to look exactly as it did in the 1990s. “It felt like stepping into a time machine,” said Dr Samtani. “When Chris and his family walked in, it was incredibly emotional — a beautiful, nostalgic moment.”

Social Frailty: The Missing Piece in Dementia Prevention

CHeBA’s research shows that social frailty - which may include loneliness, limited social contact, or few reliable relationships - can be as critical to brain health as physical and psychological wellbeing.

“We know staying socially connected is vital for brain health, but what’s missing is a simple, evidence-based checklist doctors can use,” said Dr Samtani. “Our research shows that the social frailty index has real potential to fill that gap - helping GPs identify people at higher risk and giving families a chance to act before dementia takes hold.”

Dr Samtani and his colleagues hope to see social prescribing - where doctors recommend meaningful social activities just as they prescribe medication - become a routine part of dementia prevention.

“Social isolation is the biggest modifiable risk factor for dementia in later life,” he said. “By recognising social frailty as a clinical issue, we can intervene before cognitive decline takes hold.”

A Shared Message of Hope

Both the research and the documentary share a common message: there is hope.

“If you are living with dementia or caring for someone who is, you are not alone,” said Dr Samtani. “Through awareness, social engagement and support, we can slow cognitive decline and help people live well.”

Dr Samtani also expressed heartfelt thanks to Chris Hemsworth and his family.

“Their openness and honesty will help millions understand dementia and spark meaningful conversations around the world. The documentary is beautiful and deeply moving.”

Chris Hemsworth: A Road Trip to Remember is produced by Protozoa, Nutopia, and Wild State for National Geographic.