I really like the concept of cognitive reserve when it comes to dementia. In yet another example of this idea, German investigators looked at the effect of challenging occupations in a study called Differential effects of enriched environment at work on cognitive decline in old age, published in Neurology.
In the study, 1054 subjects age 75 or older underwent cognitive testing and filled out questionnaires about the type and level of cognitive demand of their former occupations. It was found that the subjects that had been involved in careers with high demand on verbal intelligence and problem solving showed better cognitive scores, and less decline in cognition over the next 8 years after the start of the study.
The authors opine that the cognitive reserve phenomenon explains the difference. Having mentally challenging work trains the brain to perform better even later in life and protects against the damage that occurs due to aging, blood vessel deterioration, and even the harmful plaques and tangles of Alzheimers disease.
The authors also point out the importance of developing executive skills through occupational activities. Executive skills refer to complex problem solving, planning, and goal attainment which require coordination of multiple parts of the brain. Executive skills are often the first aspect of cognition to fail in the early stages of dementia, even before loss of short-term memory. Grooving brain connectivity networks during working life may delay the first manifestations of cognitive decline.
You might say that the causality in this study is the other way around: the smart, non-demented older people had challenging jobs because of these qualities, not that the challenging jobs prevented dementia or made them smarter. That’s certainly true and could explain some of the association. But the slower rate of decline from whatever level the person starts from speaks to some kind of protection of the quality of the work experience. The subjects with challenging careers are more resilient to the decrement that the average person should expect from whatever level they start from.
I’m laboring the logic here a bit, sorry! Let’s just finish by saying if your job is hard, makes you think, stay late, handle problems, meet deadlines, juggle lots of tasks, don’t fret and wish you could just sell t-shirts on the beach somewhere. Think of that job as preparation for a retirement less prone to dementia.