The Role of Physical Exercise in Cognitive Preservation: A Systematic Review.

Dementia, or major neurocognitive disorder, is one of the most common causes of disability and dependency in older adults with far-reaching social, physical, and economic impacts. In the absence of adequate treatment, much research has been directed towards prevention. Physical exercise has been shown to increase cerebral blood flow, amplify production of neurotrophic factors, and enhance brain volume. Whether these changes on a structural and cellular level result in cognitive preservation is less clear. This systematic review synthesizes findings from seventeen randomized controlled trials that examine the effects of physical activity on global cognition, memory, and executive function in older adults. Cognitive benefits of exercise are strongest for those who are cognitively intact or with mild cognitive impairment. In studies with long-term follow up, cognitive gains tended to decay after cessation of physical intervention suggesting that sustained physical exercise may be required to preserve cognitive function in older adults prior to onset of dementia.