【摘要】 目的 采用等时替代模型模拟不同体力活动、久坐行为（Sedentary Behavior, SB）相互替代后，老年人认知功能的变化。方法 采用多段分级随机抽样方法抽取南京市308名老年人。通过三维加速度计测量SB、低强度体力活动（Light Physical Activity, LPA）和中高强度体力活动（Moderate to Vigorous Physical Activity, MVPA）时间，采用蒙特利尔认知量表（MoCA）测量认知功能，使用等时替代模型评估SB、LPA、MVPA相互替代后与认知功能之间的关系。结果 (1)控制年龄、学历、佩戴时间等变量后发现，体力活动与认知功能呈正相关关系；(2)每天30 min LPA等时替代SB后，老年人计算能力（β=0.080）、定向能力（β=0.077）得分均显著增加（P<0.05）；(3)每天30 min MVPA等时替代SB后，老年人执行功能（β=0.389）、记忆力（β=0.611）、注意力（β=0.123）、计算能力（β=0.085）、语言流畅性（β=0.250）、抽象能力（β=0.168）、定向能力（β=0.080）得分均显著增加（P<0.01），反之则降低；(4)随着MVPA替代SB时间的增加，认知功能迅速上升，反之缓慢下降，而随着MVPA替代LPA时间的增加，认知功能缓慢上升，反之迅速下降。结论 (1)每天30 min LPA或MVPA等时替代SB均能不同程度地改善老年人认知功能。(2)每天30 min MVPA等时替代LPA也能改善老年人认知功能。(3)在LPA等时替代SB时，老年人认知功能缓慢上升，反之缓慢下降；在MVPA等时替代LPA时，老年人认知功能缓慢上升，反之迅速下降；在MVPA等时替代SB时，老年人认知功能迅速上升，反之缓慢下降。更多还原

【Abstract】 Objective Isochronous substitution model was adopted to simulate different physical activities and sedentary behavior(SB) to examine the changes of cognitive function of the elderly. Methods 308 elderly people in Nanjing were selected by multi-stage and hierarchical sampling method. The time of SB, light physical activity(LPA) and moderate to vigorous physical activity(MVPA) were measured by three-dimensional accelerometer.The cognitive function was measured by Montreal Cognitive Scale(MoCA). The isochronous substitution model was used to evaluate the relationships between SB, LPA and MVPA and cognitive function. Results(1) After controlling age, educational background and wearing time, a positive correlation was found between physical activity and cognitive function.(2) After 30-minute LPA isochronous substitution for SB, the computing ability of the elderly(β=0.080), directional ability(β=0.077) increased significantly(P<0.05).(3) After 30-minute MVPA isochronous substitution for SB, the performance function of the elderly(β=0.389), memory(β=0.611), attention(β=0.123), computing power(β=0.085), language ability(β=0.250), abstraction ability(β=0.168) and directional ability(β=0.080) were all significantly increased(P<0.01), otherwise it was decreased.(4) With the time increase of MVPA substitution for SB, the cognitive function increased rapidly; on the contrary, it decreased slowly. With the time increase of MVPA substitution for LPA, the cognitive function increased slowly; on the contrary, it decreased rapidly. Conclusion(1) 30-minute LPA or MVPA substitution for SB can improve the cognitive function of the elderly in varying degrees.(2) 30-minute MVPA isochronous substitution for LPA can also improve the cognitive function of the elderly.(3) With LPA substitution for SB, the cognitive function increases slowly; on the contrary, it decreases slowly. With MVPA substitution for LPA, the cognitive function of the elderly increases slowly; on the contrary, it decreases rapidly. With MVPA substitution for SB, the cognitive function of the elderly increases rapidly; on the contrary, it decreases slowly.更多还原