More than six million Americans are currently living with Alzheimer’s disease, a figure that continues to grow as the population ages. While much of the focus in Alzheimer’s research has traditionally centred on genetic predispositions and pharmacological treatments, scientists are increasingly turning their attention to modifiable lifestyle factors that may influence the likelihood of developing the disease. Researchers from Vanderbilt University Medical Center and the University of Pittsburgh have recently published compelling evidence pointing to sedentary behaviour as a significant and independent risk factor. Their findings, featured in Alzheimer’s & Dementia: The Journal of the Alzheimer’s Association, highlight how extended periods of sitting or lying down may negatively affect brain health in older adults, even when they engage in regular physical exercise.
This groundbreaking study was spearheaded by Dr Marissa Gogniat, assistant professor of Neurology at the University of Pittsburgh and a former postdoctoral fellow at the Vanderbilt Memory and Alzheimer’s Center. She collaborated closely with Dr Angela Jefferson, professor of Neurology and founding director of the exact centre at Vanderbilt University Medical Center. Together, they led a detailed investigation into the long-term effects of sedentary behaviour on brain function and structure. Their research examined 404 adults aged 50 and above who were asked to wear wrist-worn activity monitors continuously for one week. These devices recorded their daily movement patterns, allowing researchers to quantify participants’ time in sedentary states.
What set this study apart was its long-term follow-up and its integration of both cognitive assessments and neuroimaging data. Over seven years, participants underwent regular cognitive testing and brain scans. The results were stark: individuals who spent more time being sedentary were more likely to experience declines in cognitive function and to exhibit brain shrinkage in regions associated with the development of Alzheimer’s disease. Importantly, these associations persisted regardless of how much physical exercise participants reported, suggesting that sedentary behaviour—independent of overall physical activity—poses a unique threat to brain health.
A particularly striking aspect of the study was the role of genetics, specifically the presence of the APOE-e4 allele. This well-known genetic variant significantly increases the risk of developing Alzheimer’s. For those carrying this allele, the detrimental effects of prolonged sedentary time were even more pronounced. This finding suggests that reducing sedentary behaviour may be especially crucial for individuals with a genetic vulnerability, providing a behavioural target that could offset some of their inherent risk. It also implies that public health strategies aimed at Alzheimer’s prevention should be more nuanced, accounting for encouraging exercise and curbing extended periods of inactivity.
Dr Gogniat underscored this message in her commentary on the findings, noting, “Reducing your risk for Alzheimer’s disease is not just about working out once a day. Minimising the time spent sitting, even if you exercise daily, reduces the likelihood of developing Alzheimer’s disease.” Her statement challenges the belief that daily exercise alone is sufficient to maintain cognitive health in later life. Instead, the study advocates for a more dynamic and continuous approach to movement throughout the day—suggesting that frequent interruptions of sedentary periods may be just as vital as scheduled workouts.
Dr Jefferson expanded on these implications, stressing the importance of understanding how everyday choices affect long-term brain health. “Our study showed that reducing sitting time could be a promising strategy for preventing neurodegeneration and subsequent cognitive decline,” she stated. “This research highlights the importance of reducing sitting time, particularly among ageing adults at increased genetic risk for Alzheimer’s disease. It is critical to our brain health to take breaks from sitting throughout the day and move around to increase our active time.” As researchers continue to unravel the complex interplay between genetics, lifestyle, and neurodegeneration, this study reinforces a simple yet powerful message: to protect our brains as we age, we must move more and sit less.
More information: Marissa Gogniat 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, Alzheimer’s & Dementia. DOI: 10.1002/alz.70157
Journal information: Alzheimer’s & Dementia Provided by Vanderbilt University Medical Center
