Does watching TV increase dementia risk?

When it comes to sedentary activities, new research suggests some can be more damaging to cognitive health than others.

Researchers at the University of South Australia (UniSA) have assessed the 24-hour activity patterns of 397 older adults (aged 60+). Their findings suggest that the context or type of activity does matter when it comes to brain health — and more specifically, that some sedentary (or sitting) behaviours are better for cognitive function than others.

What activities are beneficial for brain health?

The researchers found that social or mentally stimulating activities such as reading, listening to music, praying, crafting, playing a musical instrument or chatting with others are beneficial for memory and thinking abilities. However, watching TV and playing video games are detrimental.

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.

It is a valuable insight that could help reduce risks of cognitive impairment, particularly when at least 45% of dementia cases could be prevented through modifiable lifestyle factors.

Context is key

“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,” said UniSA researcher Dr Maddison Mellow.

“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.”

How can people take care of their cognitive health?

“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,” Mellow said.

“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. That way you can slowly build up healthier habits.”

Image credit: iStock.com/Alican Lazutti