Sitting increases dementia risk – but it depends what activity you’re doing, scientists say

A SEDENTARY lifestyle is strongly associated with an increased risk of developing dementia.

But some sedentary behaviours are worse for cognitive function than others - which may in fact be beneficial, according to scientists.

It's that time of the year when many adults get the chance to sit back and enjoy some well-deserved down time.

But studies have shown that spending excessive time sitting down is associated with a higher likelihood of developing dementia.

Earlier this year, researchers found those who were sedentary for ten hours a day were eight per cent more likely to develop dementia than those who sat for nine hours a day.

And those sitting for 12 hours a day were 63 per cent more likely to develop the condition.

But whether you reach for the TV remote or a favourite book while sedentary, your choice could have implications for your long-term brain health, say scientists at the University of South Australia.

The researchers assessed the 24-hour activity patterns of 397 people over the age of 60.

They found the context or type of activity that people engage in, matters when it comes to brain health.

And certain activities when sitting down are better for cognitive function than others, according to the findings published in The Journals of Gerontology Series A.

The research team found that social or mentally stimulating sedentary behaviours - such as reading, listening to music, praying, crafting, playing a musical instrument, or chatting with others - are beneficial for memory and thinking abilities.

But watching TV or playing video games are detrimental, according to the study.

The researchers believe that there is likely a "hierarchy" of how sedentary behaviours relate to cognitive function, in that some have positive effects while others have negative effects.

They say it's a "valuable insight" that could help reduce risks of cognitive impairment, particularly when at least 45 per cent of dementia cases could be prevented through modifiable lifestyle factors.

The World Health Organisation (WHO) estimates that more than 55 million people have dementia globally with nearly 10 million new cases each year.

University of South Australia researcher Dr Maddison Mellow says that not all sedentary behaviours are equal when it comes to memory and thinking ability.

She said: "In this research, we found that the context of an activity alters how it relates to cognitive function, with different activities providing varying levels of cognitive stimulation and social engagement.

"We already know that physical activity is a strong protector against dementia risk, and this should certainly be prioritised if you are trying to improve your brain health.

"But until now, we hadn't directly explored whether we can benefit our brain health by swapping one sedentary behaviour for another.

"We found that sedentary behaviours which promote mental stimulation or social engagement - such as reading or talking with friends - are beneficial for cognitive function, whereas others like watching TV or gaming have a negative effect. So, the type of activity is important.

"And, while the 'move more, sit less' message certainly holds true for cardiometabolic and brain health, our research shows that a more nuanced approach is needed when it comes to thinking about the link between sedentary behaviours and cognitive function."

Dr Mellow added: "To achieve the best brain health and physical health benefits, you should prioritise movement that's enjoyable and gets the heart rate up, as this has benefits for all aspects of health.

"But even small five-minute time swaps can have benefits.

"So, if you're dead set on having a movie marathon, try to break up that time with some physical activity or a more cognitively engaged seated activity, like reading, at some point.