Alzheimers Dement

Sedentary time predicts brain decline, even in active older adults

May 19, 2025

Study details: This prospective cohort study followed 404 older adults (≥50 years) from the Vanderbilt Memory and Aging Project over seven years. Participants wore actigraphy devices for one week to objectively measure sedentary behavior and underwent repeated cognitive testing and 3T brain MRI scans. Researchers assessed the relationship between baseline sedentary time and longitudinal changes in brain structure and cognition.

Results: Greater sedentary time was associated with a smaller Alzheimer's disease (AD) neuroimaging signature and worse episodic memory in cross-sectional models. Longitudinally, increased sedentary time was associated with faster hippocampal volume reductions and declines in naming and processing speed. These associations were more pronounced in APOE-ε4 carriers.

Clinical impact: This study highlights sedentary behavior as an independent and modifiable risk factor for neurodegeneration and cognitive decline in aging adults. Even high levels of physical activity didn’t offset the negative effects of prolonged sitting.

Source:

Gogniat MA, et al. (2025, May). Alzheimers Dement. Increased sedentary behavior is associated with neurodegeneration and worse cognition in older adults over a 7-year period despite high levels of physical activity. https://pubmed.ncbi.nlm.nih.gov/40357887/