Relationships of Accelerometer-based Measured Objective Physical Activity and Sedentary Behaviour with Cognitive Function: A Comparative Cross-sectional Study of China’s Elderly Population

Abstract

This study explored the effects of physical activity and sedentary behaviour on the decline of cognitive ability among the elderly. To compensate for the limitations of self-reported physical activity, objective measures were used. A cross-sectional survey of 308 aged people mean 68.66±5.377 years, in Nanjing, China, was conducted. Physical activity was measured using the ActiGraph GT3X+, and cognitive function was measured using the Montreal Cognitive Assessment. The overall participant model, adjusted for age, BMI, education, and monthly average income, found that light physical activity (β=0.006, p<0.01), moderate-vigorous physical activity (β=0.068, p<0.001), and total physical activity (β=0.006, p<0.01) had a significant linear relationship with cognitive ability, while sedentary time did not (β=-0.020, p 0.05). Further, light physical activity only affects the cognitive ability of elderly females (β=0.006, p<0.05). There was an inverted 'U' association between moderate-vigorous physical activity and cognitive ability. The association models found that moderate-vigorous physical activity in the 22.13 min·day -1 38.79 min·day -1 range affected cognitive ability most beneficially, with the highest beta coefficient among all groups (β=0.091, p<0.05). In conclusion, while physical activity can significantly improve cognitive ability among the elderly, sedentary behaviour is associated with decreased cognitive function across genders.