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 aims to explore the effects of physical activity and sedentary behaviour on the decline of cognitive ability among the elderly. It uses objective measures to compensate for the limitations of self-reported physical activity. A cross-sectional survey of 308 people aged over 60 in Nanjing, China, was conducted. Physical activity was measured using the ActiGraph GT3X+, and cognitive function was measured using the Montreal Cognitive Assessment (MoCA). The overall participant model, adjusted for age, BMI, education, and monthly average income found that light physical activity (LPA; β=0.006, p<0.01), moderate-vigorous physical activity (MVPA; 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 (SED) did not (β=-0.020, p＞0.05). Further, LPA only affects the cognitive ability of elderly females (β=0.006, p<0.05). In addition, there was an inverted ‘U’ dose-response relationship between MVPA and cognitive ability. Dose-effect relationship models found that MVPA in the 22.13 min·day–1～38.79 min·day–1 range affected cognitive ability most beneficially. The beta coefficient was higher than the other three groups (β=0.091, p<0.05). In conclusion, while physical activity can significantly improve cognitive ability among the elderly, sedentary behaviour has no significant effect on it.