Is the lack of appropriate cognitive demand the primary driver of dementia risk?

With the general trend of increasing lifespan alongside population-level success in reducing the mortality from cardiovascular and cerebrovascular diseases, the population burden of Alzheimer's disease (AD) has steadily accelerated. [...]given the established phenomenon of demand coupling in neural tissue, we believe that this model provides the most parsimonious account of disease pathogenesis. Characterizations of downstream consequences at lower levels of organization, regardless of their level of detail, do not necessarily confer additional or greater explanatory power. A number of mechanisms linking physical activity and health, including both acute and chronic functional adaptations to exercise, have been elucidated and documented over several decades.