The large-scale investigation published in the journal PLOS Medicine and led by the University of Exeter, used data from more than 2,000 mentally fit people over the age of 65, examined the theory that experiences in early or mid life which challenge the brain make people more resilient to changes resulting from age or illness — they have higher “cognitive reserve.”

The analysis, funded by the Economic and Social Research Council (ESRC) found that people with higher levels of reserve are more likely to stay mentally fit for longer, making the brain more resilient to illnesses such as dementia.

The research team included collaborators from the universities of Bangor, Newcastle and Cambridge.

Linda Clare, Professor of Clinical Psychology of Ageing and Dementia at the University of Exeter, said: “Losing mental ability is not inevitable in later life. We know that we can all take action to increase our chances of maintaining our own mental health, through healthy living and engaging in stimulating activities. It’s important that we understand how and why this occurs, so we can give people meaningful and effective measures to take control of living full and active lives into older age.

“People who engage in stimulating activity which stretches the brain, challenging it to use different strategies that exercise a variety of networks, have higher ‘Cognitive reserve’. This builds a buffer in the brain, making it more resilient. It means signs of decline only become evident at a higher threshold of illness or decay than when this buffer is absent.”