Impact of physical activity intensity on longitudinal trajectories of cognitive function and depressive symptoms in middle-aged and older Chinese adults: Eight-year prospective study

Little is known about how longitudinal trajectories of cognitive function and depressive symptoms are impacted by varying levels of physical activity (PA) intensity.The data were from the China Health and Retirement Longitudinal Study, a nationally representative household study of the Chinese population aged 45 years and older. The sample included 5025 middle-aged and older adults (mean age = 57) who self-reported their cognitive function, depressive symptoms, and PA intensity (vigorous PA, moderate PA, and light PA) every two years from 2011 to 2018.On average, every 2 years, cognitive function decreased by 0.17 points (95 % CI: [-0.22, -0.12], P < 0.05), while depressive symptoms increased by 0.23 points (95 % CI: [0.19,0.27], P < 0.001). Middle-aged and older adults who reported a minimum of 6 days/week frequency of moderate PA (β = 0.14, 95 % CI:[0.01,0.27]) had lower reduction of cognitive function compared to people with none moderate PA but not vigorous PA (β = 0.04, 95 % CI:[-0.11,0.19]) and light PA (β = 0.06, 95 % CI:[-0.09,0.22]). The increase in depressive symptoms was significantly slower among middle-aged and older adults with a minimum of 6 days/week light PA (β = -0.02, 95 % CI:[-0.03,-0.002]).A minimum of 6 days of moderate PA a week was associated with a slower reduction in cognitive function and a minimum of 6 days of light PA a week was linked to a delayed increase in depressive symptoms. In middle-aged and older adults, a tailored PA intensity may be more beneficial in achieving the maximum improvement in cognitive function and mental health.