Mild Cognitive Impairment (MCI) is a diagnosis of cognitive decline that is greater than would be expected based on age and education, but which does not interfere significantly with daily functioning. A diagnosis of MCI indicates an increased risk for dementia, but dementia is not inevitable. In fact, some individuals with a diagnosis of MCI see an improvement in their cognitive functioning. It appears possible, but has yet to be proven, that physical activity may play a role in preventing or reversing cognitive decline in MCI. A recent commentary in Age and Ageing discusses the evidence base for possible physical interventions for MCI.
There have been many possible mechanisms identified by which physical activity might offer protective cognitive effects. It has been shown that exercise leads the body to produce several proteins that may lead to protective responses in the brain and in the vascular system. Cardiovascular health has also been associated with cognitive well-being in multiple studies, and ongoing research seems to be identifying some specific pathways through which healthy blood flow may protect certain cognitive functions. Many conditions that are provoked by inactivity, such as high blood pressure and insulin resistance, are known risk factors for cognitive decline. Thus, physical activity is known to be protective against cognitive decline.
Less is known, however, about the benefits of physical activity for individuals already diagnosed with MCI. There have been no studies yet comparing the cognitive function of active and sedentary people with a diagnosis of MCI. There is a growing body of randomized control trials (RCT) examining the effect of physical activity of moderate and high intensity on the cognitive functioning of individuals with MCI, which suggest that aerobic activity may lead to improvement in executive function, at least in the short term. These findings are promising but will require further and larger-scale study. As of now, there is no clear understanding of how physical activity programs might improve cognitive functioning, but there is ongoing research in this area. In sum, there is reason to believe that physical activity is protective against MCI, but it is not clear to what extent physical activity programs can be used to treat MCI—despite some very promising recent findings.