Summary: Extended periods of sitting or lying down in adults over 50 are linked to declines in cognition and shrinkage in brain regions vulnerable to Alzheimer’s disease. These associations appeared even among participants who reported high levels of physical activity, and were strongest in people who carry the APOE‑ε4 gene, a known genetic risk factor for Alzheimer’s. The findings suggest that interrupting sedentary time throughout the day may help protect brain health, particularly for those with increased genetic susceptibility.
A new longitudinal study from investigators at Vanderbilt University Medical Center and the University of Pittsburgh, published in Alzheimer’s & Dementia, assessed how objectively measured sedentary behavior relates to changes in brain structure and cognitive performance over seven years in older adults.
Key facts
- Independent of exercise: Greater sedentary time was associated with worse cognitive outcomes even among individuals who were otherwise physically active.
- Genetic vulnerability: Associations were more pronounced in carriers of the APOE‑ε4 allele, a common genetic risk factor for Alzheimer’s disease.
- Brain structure: More sedentary time related to accelerated shrinkage in Alzheimer’s‑sensitive brain regions, including the hippocampus, across a seven‑year follow‑up.
Source: Vanderbilt University
Researchers led by Marissa Gogniat, PhD (assistant professor of Neurology at the University of Pittsburgh and former postdoctoral fellow at the Vanderbilt Memory and Alzheimer’s Center), with senior co‑author Angela Jefferson, PhD (professor of Neurology and founding director of the Vanderbilt Memory and Alzheimer’s Center), analyzed data from 404 adults aged 50 and older enrolled in the Vanderbilt Memory and Aging Project.
Participants wore an activity monitor continuously for one week to capture objective measures of sedentary time. Researchers then related those baseline activity measurements to participants’ performance on neuropsychological tests and to structural brain MRI scans collected over a seven‑year period. Analyses controlled for physical activity levels so the impact of sedentary time could be examined independently from exercise frequency or intensity.
In cross‑sectional analyses, higher sedentary time was linked with a smaller Alzheimer’s‑related neuroimaging signature and poorer episodic memory. Longitudinal models found that greater sedentary time predicted faster reductions in hippocampal volume and declines in cognitive domains such as naming and processing speed. Importantly, several of these relationships were modified by APOE‑ε4 carrier status, with stronger effects observed in people who carry the risk allele.
“Reducing your risk for Alzheimer’s disease is not just about working out once a day,” Gogniat said. “Minimizing the time spent sitting, even if you do exercise daily, reduces the likelihood of developing Alzheimer’s disease.” Jefferson emphasized the broader implications, noting that studying lifestyle choices and their long‑term effects on brain health is critical as the population ages.
The authors suggest that regular breaks from sitting—brief periods of standing or light movement throughout the day—could be a practical, scalable strategy to help prevent neurodegeneration and cognitive decline, especially for older adults with higher genetic risk. While more research is needed to define optimal timing and patterns for interrupting sedentary time, these findings reinforce public health messages that both increasing physical activity and reducing prolonged sitting matter for brain health.
Funding: The study received support from the Alzheimer’s Association and the National Institute on Aging.
About this sedentary behavior and Alzheimer’s disease research news
Author: Craig Boerner, Vanderbilt University
Source: Vanderbilt University
Contact: Craig Boerner – Vanderbilt University
Image: The image is credited to Neuroscience News
Original research (open access): “Increased sedentary behavior is associated with neurodegeneration and worse cognition in older adults over a 7‑year period despite high levels of physical activity” by Marissa Gogniat et al. Published in Alzheimer’s & Dementia. DOI: 10.1002/alz.70157
Abstract
Increased sedentary behavior is associated with neurodegeneration and worse cognition in older adults over a 7‑year period despite high levels of physical activity
INTRODUCTION
Sedentary behavior may be a modifiable risk factor for Alzheimer’s disease (AD). This study examined how objectively measured sedentary time relates to longitudinal changes in brain structure and cognition in older adults.
METHODS
Participants from the Vanderbilt Memory and Aging Project (n = 404) completed seven days of actigraphy, comprehensive neuropsychological testing, and 3T brain MRI scanning across a seven‑year follow‑up. Cross‑sectional and longitudinal linear regression models assessed relationships between sedentary time, brain structure, and cognition. Models were repeated to test whether apolipoprotein E (APOE) ε4 status modified these associations.
RESULTS
Cross‑sectionally, greater sedentary time was associated with a smaller AD‑neuroimaging signature and poorer episodic memory. Associations varied by APOE‑ε4 carrier status. Longitudinally, higher sedentary time predicted faster hippocampal volume loss and greater declines in naming and processing speed over seven years.
DISCUSSION
These results support reducing sedentary time as a potentially important strategy for protecting brain structure and cognitive function with age, particularly for adults at increased genetic risk for Alzheimer’s disease.