Cutting Back on Sitting Time May Help Prevent Alzheimer’s

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Spending too much time sitting could lead to faster memory decline and changes in the brain that are linked to Alzheimer’s disease, particularly in people who carry a gene that increases Alzheimer’s risk, according to research conducted at Vanderbilt University.

Sedentary behavior has been previously linked to an increased risk of chronic diseases, including cardiovascular disease, Type 2 diabetes and cancer. Now, recent research has suggested too much time spent sitting down could also be associated with cognitive decline and Alzheimer’s disease.

However, investigators believe “reducing sedentary behavior time may hold promise as an effective strategy to prevent neurodegeneration.”

The Study

The team followed 404 older adults, recruited from the Legacy and Expansion Cohorts of the Vanderbilt Memory and Aging Project (VMAP), for up to seven years.

Participants wore activity trackers (actigraphy) 24 hours a day for 10 consecutive days to measure how much time they spent being sedentary (not physically active), such as sitting, watching television or lying down while awake. They also had regular brain scans via MRI to look at brain structure as well as memory and thinking (cognitive) tests that assessed language, executive function, episodic memory, processing speed and visuospatial ability.

Some participants had a version of the APOE gene called APOE ε4, which is known to raise the risk of developing Alzheimer’s disease. The investigators wanted to examine whether the impact of sedentary time was worse in people with this gene.

The Findings

The average age of patients was 71 years, most were White (85%), and approximately one-third of participants were APOE-ε4 positive.

More sedentary time was linked to the following:

• Smaller brain regions associated with Alzheimer’s (called the AD neuroimaging signature)
• Worse memory performance at the start of the study

Over time, people who were more sedentary also experienced the following:

• Faster shrinkage in the hippocampus (a brain area crucial for memory)
• More decline in language skills (naming objects)
• Slower processing speed (how quickly you can take in and use information)

Worse function was observed among those who had more sedentary time despite relatively high levels of physical activity among the cohort.

These changes were especially strong in people who carried the APOE ε4 gene — meaning they may be more vulnerable to the harmful effects of too much sitting.

“Reducing your risk for Alzheimer’s disease is not just about working out once a day,” said lead investigator Marissa Gogniat, Ph.D., assistant professor of neurology at the University of Pittsburgh and former postdoctoral fellow at the Vanderbilt Memory and Alzheimer’s Center. “Minimizing the time spent sitting, even if you do exercise daily, reduces the likelihood of developing Alzheimer’s disease.”

Investigators mentioned several important strengths of the study, including following a large group of older adults from the community who were carefully assessed over time.

However, there were also some limitations to keep in mind. Most of the participants were White, highly educated and quite physically active — 87% met recommendations of at least 150 minutes of physical activity per week. Because of this, the findings may not apply to all older adults, especially those from more diverse or less active populations.

Despite these limitations, the study provides strong evidence that reducing sedentary time may benefit brain health, even in people who are already physically active.

“This research highlights the importance of reducing sitting time, particularly among aging adults at increased genetic risk for Alzheimer’s disease,” said co-author Angela Jefferson, Ph.D., professor of neurology and founding director of the Vanderbilt Memory and Alzheimer’s Center at Vanderbilt University Medical Center. “It is critical to our brain health to take breaks from sitting throughout the day and move around to increase our active time.”