Physical activity and cognition in Alzheimer's disease: relationship to vascular risk factors, executive functions and gait.

Epidemiological studies show a positive relationship between physical activity and cognition in patients with Alzheimer's disease (AD). A relatively small number of intervention studies have examined the effects of physical activity, such as walking, on cognition in AD patients. The results of these studies, reviewed here, include both positive and negative findings. The finding that physical activity does not improve cognition in all AD patients could be explained by two factors that have received little attention thus far: executive dysfunction and gait disturbances. These two factors are part of a cascade of events, initiated by cerebrovascular disease in AD. This cascade of events is addressed in detail. Finally, (non)pharmacological interventions to improve executive dysfunctions and gait disturbances in patients with AD are discussed.