The benefits of physical exercise on older adults’ cognitive function: a cohort study exploring potential mechanisms

Despite existing studies showing that physical exercise improves cognitive function in older adults either concurrently or in a delayed manner, studies examining these associations simultaneously are rare. Additionally, the underlying mechanisms in these associations remain incompletely understood. This study explores the concurrent and delayed (two years later) associations between physical exercise and older adults' cognitive function. This study also investigates the mediating roles of three negative physical, psychological, and social resources: limitations in daily abilities, depressive mood, and isolation from friends, as well as the moderating roles of cognitive reserve on these associations. A cohort sample of 6,646 Chinese older adults (Mean age = 69.28, SD = 7.03) is obtained from the 2016 and 2018 waves of the China Longitudinal Aging Social Survey. Regression analysis was employed to test the concurrent and delayed associations between physical exercise and cognitive function. The bootstrap method was utilized to examine the mediating roles of limitations in daily activities, depression mood, and isolation from friends. Interaction terms were generated to investigate the moderating roles of cognitive reserve. Physical exercise presents concurrent and delayed positive associations with cognitive function. Limitations in daily activities, depressive mood and isolation from friends mediate the above associations. Moreover, cognitive reserve plays a significant role in buffering the concurrent and delayed negative links between depressive mood, isolation from friends, and cognitive function, with larger negative relationships observed for older adults with lower rather than higher levels of cognitive reserve. This study validates the concurrent and delayed benefits of physical exercise on older adults' cognitive function while elucidating the underlying mechanisms. These findings offer practical implications for health policies and intervention programs aimed at enhancing older adults' cognitive function.