Are active brains more resistant to dementia?

Can keeping mentally fit reduce the risk of dementia?

Frequent cognitive activity in old age has been associated with reduced risk of Alzheimer’s Disease – although it isn’t yet certain why.

One possible explanation is that if we stay mentally active throughout our lives, by developing new interests and skills, then this develops our brain and builds some form of reserve in it which helps protect against or compensate for dementia. This is known as the Cognitive Reserve hypothesis.

Perhaps bigger or denser brains can tolerate more loss before brain functions are impaired. Perhaps the same brain networks have been helped to work more efficiently. Or perhaps the brain is able to shift operations to alternative circuits.

Whatever the mechanism a number of studies support the idea of a Cognitive Reserve. For example researchers at Rush University Medical Centre in Chicago observed 1,076 people with an average age of 80, who were free from dementia, over a 5 year period. The people studied were asked to report how often they read the newspaper, wrote letters, visited a library and played board games such as chess. “The results suggest a cause and effect relationship: that being mentally active leads to better cognitive health in old age." according to the lead researcher (reported in Neurology online).

Can leisure activities help if they exercise the brain?

Participation in leisure activities has also been associated with a lower risk of dementia. However it isn’t yet clear whether increased participation in leisure activities actually does lower the risk of dementia or if participation in leisure activities declines during the preclinical phase of dementia i.e. when dementia is already present but the symptoms are not yet clear.

Research published in the New England Journal of Medicine in 2003 suggested that a number of leisure activities were associated with a reduced risk of dementia. These were: reading books or newspapers, playing board games or cards, doing crosswords, playing musical instruments, and dancing. 

A more recent study was published in 2013. It aimed to explore whether combining physical and mental activitywould improve cognitive functioning. 126 inactive, community-residing older adults with cognitive complaints participated. The researchers concluded, ‘12 weeks of physical plus mental activity was associated with significant improvements in global cognitive function.’

A 2016 review of published evidence concluded, 'there is increasing evidence that participation in cognitively stimulating leisure activities may contribute to a reduction of risk of dementia.'

Passive leisure activities, like watching TV, unfortunately seem to hinder rather than help. A study reported in 2006 looked at 5,437 older people over a 5 year period. It found, ‘watching television was associated with an increased risk of cognitive impairment.’

What about staying socially active?

The Alzheimer's Association recommends remaining socially active. It reports that research suggests it is good for the brain - particularly when combined with mental and physical activity. So stay connected with your family and friends or get reconnected. Other options include joining a book club, sports club, volunteer group, continuing education class or community activity. 

What about brain training?

Research here has shown mixed results. However, one specific type of computerized brain training, known as speed of processing or useful field of view training, has shown promising results.  

Can staying physically active help too?

Some long term studies have suggested that physical activity helps protect the brain, although the results are mixed. A review of 17 trials, published in 2015, concluded that exercise programmes could help people living with dementia to perform daily activities and wasn't harmful but didn't appear to have other benefits for the brain where people already had dementia.

However, if we consider people who don't yet have dementia, the results appear more promising. A 2015 review of the evidence concluded, 'physical activity improves cognitive function through a host of different pathways.' Whilst a 2014 review of forty seven long term observational studies noted that these studies showed an association (albeit not yet a proven cause and effect relationship) between higher levels of physical activity and a reduced risk of cognitive decline and dementia.' And a 2014 study suggested that physical activity could be helpful for memory where people are at particular genetic risk of dementia.

Conclusions

  • Keeping mentally active throughout our lives seems to be associated with a reduced risk of cognitive impairment and dementia.
  • It may be that this mental activity builds a ‘cognitive reserve’ which helps protect the way our brain functions as we get older.
  • Keeping physically active and socially active also seem to be associated with a reduced risk of dementia.

Delia Morick October 2013, Reviewed and updated by Charlotte Christopherson February 2017, Next review date January 2020

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