Sitting too long contributes to weight gain, inflammation, heart disease, and diabetes.¹² New research suggests this behavior is also linked to Alzheimer’s disease, cognitive decline, and brain shrinkage—even in people who exercise regularly.³

Gogniat MA, Khan OA, Li J, et al. Increased sedentary behavior is associated with neurodegeneration and worse cognition in older adults over a 7‐year period despite high levels of physical activity. Alzheimers Dement. 2025;21(5):e70157. doi:10.1002/alz.70157

What the Study Found

The seven-year study, published in the journal Alzheimer’s & Dementia, included over 400 older adults without dementia. Participants wore activity trackers on their wrists, received MRI scans, and were tested for the APOE-e4 gene, which indicates Alzheimer’s disease risk.

More sitting time was associated with worse cognitive health and shrinkage in parts of the brain, especially for APOE-e4 carriers.

“When we accounted for everyone’s physical activity, more sedentary behavior still predicted greater cognitive decline and neurodegeneration, suggesting that sedentary behavior may independently contribute to risk for Alzheimer’s disease regardless of how much you exercise,” Marissa A. Gogniat, PhD, lead author of the study and assistant professor of neurology at the University of Pittsburgh School of Medicine, told Verywell.

Nearly 90% of the study participants got the recommended 150 minutes of physical activity according to their activity tracking devices.

“People who are physically active might also consider how much they are sitting,” Gogniat added.

Why Is Sitting So Bad for the Brain?

It remains unclear why sitting contributes to brain shrinkage and Alzheimer’s disease.

“I think this is the million-dollar question that we still don’t fully understand yet,” Gogniat said.

Sedentary behavior could contribute to increased inflammation, vascular changes in the body and brain, or reduced synaptic plasticity—a key part of learning and memory. These pathways may link prolonged sitting with brain shrinkage, according to Gogniat.

“I would hypothesize that sedentary behavior increases overall inflammation in the brain,” David Hunter, MD, an associate professor of neurology at UTHealth Houston who was not involved with the study, told Verywell.

A 2019 study found that having higher levels of inflammatory markers in the body was associated with 7.8% steeper cognitive decline.⁴ However, more research is needed to better understand the relationship between sitting and brain health.

What You Do While Sitting Could Matter

Sitting may not always contribute to cognitive decline. Existing research suggests that “cognitively demanding” sedentary behaviors, such as reading and playing cards, may offer cognitive benefits, but watching TV does not.⁵

“We are still investigating the impact of what you are doing while you are sitting, but there is some evidence to suggest that more cognitively stimulating activities, like reading, may be more beneficial than less stimulating ones,” Gogniat said.

A Taiwanese study published in 2021 found that people who read more frequently experienced less cognitive decline long term, regardless of their education level.⁶

Move More for Brain Health

You don’t have to move all day for brain health, but it’s important to take movement breaks when you can.

“I try to break up long periods of sitting at work by taking a stroll down the hallway or walking on my walking pad during off-camera meetings,” Gogniat said.

The Centers for Disease Control and Prevention (CDC) estimates that it is possible to delay or prevent 45% of dementia cases.⁷ Moving more and breaking up sedentary behavior may help, but these factors alone won’t fully prevent cognitive decline.

Managing high blood pressure and diabetes, correcting hearing loss, and avoiding alcohol and smoking can also help lower Alzheimer’s and dementia risk.⁷

“Avoiding a sedentary lifestyle is not a goal to follow in a vacuum, but as part of an overall healthy lifestyle. In other words, there is no silver bullet that will prevent Alzheimer’s disease,” Hunter said.

What This Means For You

New research suggests that sitting too long can affect your brain. Specifically, it’s linked to Alzheimer’s disease, cognitive decline, and brain shrinkage, even in people who consistently exercise. Breaking up time sitting with short walks or movement can help.

Sources:

1. Johns Hopkins Medicine. Sitting disease: how a sedentary lifestyle affects heart health.
2. MedlinePlus. Health risks of an inactive lifestyle.
3. Gogniat MA, Khan OA, Li J, et al. Increased sedentary behavior is associated with neurodegeneration and worse cognition in older adults over a 7‐year period despite high levels of physical activity. Alzheimers Dement. 2025;21(5):e70157. doi:10.1002/alz.70157
4. Walker KA, Gottesman RF, Wu A, et al. Systemic inflammation during midlife and cognitive change over 20 years: the ARIC Study. Neurology. 2019;92(11). doi:10.1212/WNL.0000000000007094
5. Mellow ML, Crozier AJ, Dumuid D, et al. How are combinations of physical activity, sedentary behaviour and sleep related to cognitive function in older adults? A systematic review. Exp Gerontol. 2022;159:111698. doi:10.1016/j.exger.2022.111698
6. Chang YH, Wu IC, Hsiung CA. Reading activity prevents long-term decline in cognitive function in older people: evidence from a 14-year longitudinal study. Int Psychogeriatr. 2021;33(1):63-74. doi:10.1017/S1041610220000812
7. Centers for Disease Control and Prevention. Reducing risk for dementia.

Important Notice: This article was originally published at www.verywellhealth.com by Stephanie Brown, where all credits are due. Fact checked by Jennifer Klump