Research demonstrated that what older adults do when they are sitting influences their risk of dementia.
According to a recent study by the University of Southern California and University of Arizona researchers, those 60 and older who spend a lot of time watching TV or partaking in other passive, sedentary behaviors may be more likely to develop dementia.
Additionally, their research demonstrated that the risk is reduced for those who engage in activities while seated, such as reading or using a computer.
The study was published recently published in Proceedings of the National Academy of Sciences. It also revealed that even among those who engaged in physical activity, the connection between sedentary behavior and the risk of dementia persisted.
“It isn’t the time spent sitting, per se, but the type of sedentary activity performed during leisure time that impacts dementia risk,” said study author David Raichlen, professor of biological sciences and anthropology at the University of Southern California Dornsife College of Letters, Arts and Sciences.
“We know from past studies that watching TV involves low levels of muscle activity and energy use compared with using a computer or reading,” he said. “And while research has shown that uninterrupted sitting for long periods is linked with reduced blood flow in the brain, the relatively greater intellectual stimulation that occurs during computer use may counteract the negative effects of sitting.”
Researchers looked at potential links between dementia in older adults and sedentary leisure activities using self-reported data from the U.K. Biobank, a large biomedical database with more than 500,000 participants throughout the United Kingdom.
During the 2006–2010 baseline assessment period, more than 145,000 people aged 60 and over who were not diagnosed with dementia completed touchscreen questionnaires to self-report information on their levels of sedentary behavior.
The researchers analyzed hospital inpatient data to identify dementia diagnoses after an average of almost 12 years of follow-up. 3,507 positive cases were discovered.
Then, the researchers made adjustments for certain demographics (such as age, sex, race/ethnicity, and kind of job) and lifestyle factors (such as exercise, smoking and alcohol use, amount of sleep, and social interaction) that could have an impact on brain health.
The impact of physical activity and mental activity on the risk
The results remained the same even after the scientists accounted for levels of physical activity. Even in individuals who are highly physically active, time spent watching TV was associated with an increased risk of dementia, and leisure time spent using a computer was associated with a reduced risk of developing dementia.
“Although we know that physical activity is good for our brain health, many of us think that if we are just more physically active during the day, we can counter the negative effects of time spent sitting,” said study author Gene Alexander, professor of Psychology and Evelyn F. McKnight Brain Institute at the University of Arizona.
“Our findings suggest that the brain impacts of sitting during our leisure activities are really separate from how physically active we are,” said Alexander, “and that being more mentally active like when using computers, may be a key way to help counter the increased risk of dementia related to more passive sedentary behaviors, like watching TV.”
Knowing how sedentary activities impact human health could lead to some improvements.
“What we do while we’re sitting matters, ” Raichlen added. “This knowledge is critical when it comes to designing targeted public health interventions aimed at reducing the risk of neurodegenerative disease from sedentary activities through positive behavior change.”
Reference: “Leisure-time sedentary behaviors are differentially associated with all-cause dementia regardless of engagement in physical activity” by David A. Raichlen, Yann C. Klimentidis, M. Katherine Sayre, Pradyumna K. Bharadwaj, Mark H. C. Lai, Rand R. Wilcox and Gene E. Alexander, 22 August 2022, Proceedings of the National Academy of Sciences.
The study was funded by the National Institutes of Health, the state of Arizona and Arizona Department of Health Services, and the McKnight Brain Research Foundation.