Two activities MILLIONS of people do while sitting raise dementia risk, warn experts
It's well known that spending too much time spent sitting on our backside can raise the risk of a multitude of diseases - from diabetes to dementia.
But scientists have found that, when it comes to protecting the brain from age-related decline, there are some sedentary activities that may be beneficial.
Researchers from the University of South Australia have developed a 'hierachy' of pasttimes performed while sitting down, and say some have more positive brain effects than negative.
At the top of the 'beneficial list' are activities said to be mentally or socially stimulating - like reading, listening to music, praying, crafting, playing a musical instrument, or chatting with others.
The scientists said these behaviours improved memory and thinking abilities, which helps protect against dementia in later life.
But worst for the brain are watching television and playing video games.
A wealth of research has suggested that prolonged television watching is linked to reduced gray matter in the brain - crucial for thinking, reasoning, decision making and a host of other important cognitive functions.
Imaging studies show that the less gray matter within a person's brain, the poorer their cognitive skills.
Previous studies have found that watching television for more than three hours frequently can impair learning and memory skills.
Experts believe this may be due to a lack of stimulation causing connections between brain cells to die off.
For the new study, researchers assessed the 24-hour activity patterns of 397 people over the age of 60.
They then tested participants' cognitive abilities using two written tests used by experts to spot signs of dementia, or declining brain health.
Writing in the medical journal, The Journals of Gerontology Series A, the scientists reported those who spent more time doing 'mentally stimulating' sedentary activities performed far better on cognitive tests.
'We already know that physical activity is a strong protector against dementia risk,' said co-author Dr Maddison Mellow.
'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 that 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.
People who regularly read books, played musical instruments or keep a personal diary have a 23 per cent lower risk of developing the condition
'So, the type of activity is important.
'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 cognitive function.'
Dr Mellow advised older adults to intersperse the more passive activities with engaging ones, even if just for five minutes at a time.
'Small five minute time swaps can have benefits,' she said. '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.'
Polls have found that around half of Brits say they're happy to watch back-to-back episodes of television shows for up to four hours.
The new study echoes previous findings about the risks of Netflix binges for brain health.
In 2019, British researchers published research that revealed watching television for over three and a half hours a day is linked to a decline in performance on word learning and recall tasks.
The researchers first measured how much television 3,590 people over the age of 50 watched on average each day.
They then categorised study participants into five categories, based on how much television they watched.
The researchers also used tests to measure verbal memory and thinking twice - six years apart.
They found that watching television for more than three and a half hours a day is associated with poorer verbal memory.
Some 944,000 people in the UK have dementia, with Alzheimer's Disease the most common type.
Dementia was the leading cause of death in the UK in 2023 – with 75,393 people dying last year, compared with 74,261 in 2022 and 69,178 in 2021, according to Alzheimer's Research UK.
Research indicates that around half of all cases are due to lifestyle factors such as smoking, poor diet, obesity, lack of exercise and infrequent mental stimulation.
