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Social interaction doesn’t just make us happy – it helps to slow down brain ageing, a study by the Centre for Healthy Brain Ageing (CHeBA) at UNSW Sydney finds.

The study, published in The Lancet Healthy Longevity, identified different types of social interactions that are associated with reduced cognitive decline as we age.

“We knew that people who are isolated are at greater risk of dementia. But what we didn’t know is what kinds of social interactions we need to keep our brain healthy,” said first author Dr Suraj Samtani, who is a clinical psychologist and researcher at CHeBA.

“And how much do we need to keep our brain healthy? We wanted to answer those two questions so that we could give some very specific guidelines to everyone.”

Dr Suraj Samtani

Dr Suraj Samtani is a researcher at CHeBA and clinical psychologist. Photo: Supplied.

According to study co-author Professor Henry Brodaty AO, who is the Co-Director of CHeBA, this research can help us to take measures to prevent cognitive decline.

“Through research such as this we are able to develop and implement societal shifts to reduce risk of memory decline and dementia,” Professor Brodaty said.

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The study was a meta-analysis, combining data from over 38,000 participants in 13 previous studies across every continent. Participants had been followed for several years with data collected on who they socialised with and how much, as well as their cognitive capacity.

“There were some review studies that took data from North America and Europe and found that being married or being in a relationship or living with others might be [important],” said Dr Samtani. “But we didn't really have evidence from beyond those countries, and we didn't have evidence on all the other types of social things that we could be doing.”

Reducing stress and stimulating the brain

As the study participants aged, having social interactions was associated with slower decline in cognitive function. The effect was especially strong for those who were in a relationship or married, as well as those living with others.

“We found that especially living with others, being in a relationship and never feeling lonely were associated with slower cognitive decline,” said Dr Samtani.

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So how does having these relationships protect against cognitive decline? The researchers think that there are two ways social interaction might help healthy brain ageing.

“One way is that having other people there provides us with stimulating activities, and just talking to people uses your memory and language skills,” said Dr Samtani. “The other way is having support from other people, which reduces how much stress you feel. Lowering your stress keeps your brain healthier for longer.”

Introverts, don’t fret

Is your calendar not exactly bursting with social events? Not to worry – the study showed that any social interaction is better than no interaction to keep your brain healthy. For example, yearly, monthly or weekly engagement in a community group was associated with slower memory decline than no engagement.  

This finding is particularly important for those who do not have a partner, live alone or have less opportunity to spend time with friends and family. Engaging with the community through volunteering, interest groups and other activities can also stimulate the mind and reduce stress, slowing down brain ageing.  

“I think the most important thing is that our findings give everyone a lot of hope… Even if it’s a few times a year or once a month, that’s still better than having no social interaction,” said Dr Samtani.

“Our message is to get out there, talk to someone, have a coffee with someone… stay active.”