Spending Too Much Time Sitting Could Raise Your Alzheimer’s Risk
A new study found that sedentary behavior may increase Alzheimer's disease risk in aging adults—regardless of how much they exercised
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- In a new study, more time spent sitting was linked to higher Alzheimer’s risk in older adults.
- This finding held true regardless of how much people exercised.
- While exercise supports brain health, it can’t offset hours of sitting—experts recommend breaking up those sedentary periods with walking, stretching, or other light movement.
Spending more time sitting could be bad for your brain health, a new study suggests.
The research found that older adults who spent more time sitting and lying down also had poorer cognitive function and shrinkage in parts of the brain tied to Alzheimer’s disease risk. This link between sedentary behavior and Alzheimer’s stood firm regardless of the participants’ exercise level.
The study was published on May 13 in the journal Alzheimer’s & Dementia.
Alzheimer’s disease, a progressive neurodegenerative disease that causes decreased memory and cognitive function, affects more than 7 million people in the U.S. alone. And cases are projected to hit 13 million by 2050.
“This study is an important contribution to the growing body of evidence showing that how we move—or don’t move—throughout the day can meaningfully affect brain health,” said Prabha Siddarth, PhD, a research statistician at the Semel Institute for Neuroscience and Human Behavior at UCLA. “Sedentary behavior itself may be an independent risk factor for Alzheimer’s disease.”
Investigating the Link Between Sitting and Alzheimer’s
Though there’s been plenty of research illustrating that more exercise lowers dementia risk, study author Marissa Gogniat, PhD, told Health she wanted to know whether people’s activity levels over the course of a whole day might impact their Alzheimer’s risk, too.
So Gogniat, an assistant professor of neurology at the University of Pittsburgh and a former postdoctoral fellow at the Vanderbilt Memory and Alzheimer’s Center, studied a group of 404 older adults to find out.
Study participants wore a smartwatch that recorded their activity levels for one week, and had various neuropsychological assessments and brain MRIs over a seven-year period. On average, participants spent about 13 hours sitting or lying down throughout the day.
Results showed that, regardless of exercise level, people who spent more time sitting and lying down had:
- Worse episodic memory
- Lower scores on various cognitive performance tests
- Greater declines in volume in certain areas of the brain
- Smaller Alzheimer’s neuroimaging signature, which is linked to a greater risk of cognitive decline in the future
The association between sedentary behavior and Alzheimer’s risk was even more significant for those who had a genetic risk factor for the disease, called the APOE-ε4 allele.
This research “fills a critical gap” in how we understand movement and risk for cognitive decline, Siddarth explained, and further builds on the idea that lifestyle behaviors can impact how the brain functions.
However, the study is just a jumping off point. Notably, the group of participants recruited for this study were “highly educated, mostly non-Hispanic white” and “already relatively active,” Siddarth explained, which “does not reflect the broader population, especially communities at higher risk for Alzheimer’s disease.” More research is needed, she said.
Why Might Sitting More Increase Alzheimer’s Risk?
The “million-dollar question” behind this research, Gogniat said, is why exactly being sedentary could increase someone’s chances of getting Alzheimer’s. And for now, that question still doesn’t have a definitive answer.
However, there are “several biologically plausible pathways” that could explain what’s going on, Siddarth explained.
”Brain health is closely tied to vascular and metabolic health, and long periods of inactivity may have downstream effects on these systems,” she said.
According to Siddarth and Gogniat, spending more time being sedentary could:
- Increase inflammation
- Reduce blood flow to the brain
- Impair glucose or lipid metabolism
- Reduce synaptic plasticity, or the brain’s ability to adapt and make necessary changes in neuron connections
- Lead to changes in insulin sensitivity
All of these factors “may contribute to neurodegeneration,” said Siddarth.
Why Didn’t Exercise Help Mitigate This Risk?
Given exercise’s known cognitive benefits, it’s striking that more physical activity among the study’s participants didn’t seem to make a difference in their Alzheimer’s risk.
This doesn’t necessarily contradict that idea: Siddarth stressed that exercise is still “a powerful modulator of brain health,” and that it’s been shown to reduce inflammation, support vascular and metabolic function, and enhance the formation of new neurons in the brain.
“However, the nuance here is important,” she said. “Being active for 30 minutes a day doesn’t necessarily counteract the effects of being sedentary for the other 15 to 16 waking hours.”
In other words, “exercise and sedentary behavior are not two ends of a single spectrum,” so it’s possible for someone to exercise daily but also live a largely sedentary life, Siddarth added. But the exact logistics of how much time you should spend moving versus sitting each day are still unknown.
“There is a lot more to explore,” said Gogniat.
Incorporating More Movement Into Your Day
This latest study—and others like it—suggest that movement is an incredibly important way to protect your cognitive health, Siddarth said. That’s especially true for people at a higher genetic risk for Alzheimer’s or dementia more broadly, experts agreed.
“Movement throughout the day helps maintain vascular health, supports brain [blood flow], and may reduce the accumulation of Alzheimer’s-related pathology,” said Siddarth.
But that doesn’t necessarily mean that you need to run a marathon or exercise for hours each day to keep your brain healthy: Rather, think about ways to break up sitting periods, Gogniat explained.
To that end, experts recommend:
- Setting a timer to stand up and stretch every half hour
- Walking during phone calls or in between meetings
- Investing in a walking pad or a standing desk
- Parking further from entrances
- Taking the stairs instead of the elevator
- Trying chair-based movements if you have mobility concerns
“Every movement counts,” Siddarth said. “The message is not just ‘exercise more,’ but ‘sit less’.”
Julia Landwehr
Julia is the associate news editor for Health, where she edits and publishes news articles on trending health and wellness topics. Her work has been featured in The Heights, an independent student newspaper at Boston College, and Minnesota Monthly.
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This story originally appeared on: Health News - Author:Brian Mastroianni
