Physical activity has been shown to be positively associated with cognitive health, but the mechanisms underlying the benefits of physical activity on cognitive health are unclear. The present study simultaneously examined two hypotheses using structural equation modeling (SEM). The depression-reduction hypothesis states that depression suppresses cognitive ability and that physical activity alleviates dysphoric mood and thereby improves cognitive ability. The social-stimulation hypothesis posits that social contact, which is often facilitated by socially laden physical activities, improves cognitive functioning by stimulating the nervous system. Sedentary behavior in the absence of physical activity is expected to exert an inverse relationship on cognitive health through each of these hypotheses. Community-dwelling elders (N = 158) were administered a variety of measures of cognition, depression, social support, and physical activity. SEM techniques provided partial support for the social-stimulation hypothesis and depression-reduction hypothesis. Implications for treating depression and improving cognitive functioning are discussed.
David E. Vance, Virginia G. Wadley, Karlene K. Ball, Daniel L. Roenker and Matthew Rizzo
David E. Vance, Karlene K. Ball, Daniel L. Roenker, Virginia G. Wadley, Jerri D. Edwards and Gayla M. Cissell
Falls can impair health and reduce quality of life among older adults. Although many factors are related to falling, few analyses examine causal models of this behavior. In this study, factors associated with falling were explored simultaneously using structural-equation modeling. A variety of cognitive, physical-performance, and health measures were administered to 694 older adult drivers from the state of Maryland. The observed and latent variables of age, cognitive ability, physical functioning, health, and falling behavior were used to create a causal model. The model revealed that being older was associated with declines in cognition, and such cognitive declines predicted increased falling. Similarly, poorer health was related to poorer physical functioning, which, in turn, also predicted increased falling. This model indicates that in addition to existing fall-prevention interventions aimed at improving physical functioning, interventions to improve cognition and health might also be effective. It is speculated that fear of falling, which often results in reduced mobility among older adults, might account for the lack of a direct relationship between age and falling. This hypothesis should be examined in further research.