- Previous research has shown that making certain unhealthy lifestyle choices, such as living a sedentary lifestyle, may increase a person’s risk for dementia.
- A new study has found that mentally active sedentary behaviors may help lower a person’s dementia risk.
- Among these mentally active behaviors were habits such as reading a book, solving a crossword puzzle, or learning a new skill.
According to Alzheimer’s Disease International, in 2020, more than 55 million people globally were living with dementia — a group of cognitive disorders, such as Alzheimer’s disease, that negatively impact a person’s memory and thinking skills.
Previous research has shown that making certain unhealthy lifestyle choices, such as living a sedentary lifestyle, may increase a person’s risk for dementia.
Now, a new study published in the American Journal of Preventive Medicine says that not all sedentary activities are the same, and mentally active sedentary behaviors — such as reading a book, solving a crossword puzzle, or participating in a school classroom — may actually help reduce a person’s dementia risk.
For this study, researchers analyzed health data from more than 20,000 adult participants between the ages of 35 and 64 years in the Swedish National March Cohort.
Participants’ active and passive sedentary activities were monitored via questionnaires.
“Mentally passive sedentary behaviors are those that involve very little conscious ‘mental effort’, such as watching TV,” Mats Hallgren, PhD, principal researcher in the Department of Public Health Sciences at the Karolinska Institute in Sweden, associate professor in the Baker-Deakin Department of Lifestyle and Diabetes in the Institute for Physical Activity and Nutrition (IPAN) at Deakin University in Australia, and lead author of this study, told Medical News Today. “This does not mean your brain activity stops completely, but rather, it slows down significantly.”
“By contrast, mentally-active sedentary behaviors are those that require sustained mental (or cognitive) effort, such as reading a book, problem solving, engaging in complex work-related tasks, etc. We decided to examine these types of behaviors because, firstly, they are ubiquitous in daily life, and secondly, we found them to be differentially associated with depression in a previous study.”
— Mats Hallgren, PhD
“Specifically, we observed that longer average durations of mentally passive sedentary behaviors significantly
At the study’s conclusion, researchers found that engaging in mentally active sedentary behaviors was correlated with a lower chance of developing dementia among middle-aged and older adults.
“This new finding is significant because we have identified what appears to be a novel risk factor for dementia,” Hallgren said. “The study requires replication, but if similar findings emerge in different populations, this would indicate the need to amend existing physical activity and dementia risk guidelines with the aim of minimizing mentally passive sitting time, for example, by replacing it with mentally active sitting, or with light physical activity — to the extent that it is feasible in everyday life.”
Additionally, scientists discovered that replacing the amount of time spent in mentally passive sedentary activities with time-equivalent durations of mentally active sedentary behaviors also led to a decreased risk for dementia.
“This finding suggests that there is a practical way to attenuate or even eliminate the deleterious effects of extended mentally passive sitting time on dementia risk,” Hallgren explained. “By simply replacing it with more mentally engaging activity (sedentary or movement-based), we can greatly offset these risks. It is also noteworthy that some mentally passive sitting time is probably unavoidable, and unlikely to cause any significant harm.”
“Physical activity is vital for sustained health and vitality as we age, but so is mental activity. This is especially the case when we are sitting for extended periods. Sit less and move more, more often. If you have to sit, try to break up long periods of passive sitting with something that you find mentally engaging and/or challenging.”
— Mats Hallgren, PhD
MNT spoke with Dung Trinh, MD, internist for MemorialCare Medical Group and chief medical officer of Healthy Brain Clinic in Irvine, CA, about this study, who commented that his first reaction to its findings was that it adds a very useful layer of nuance to the conversation around sitting and brain health.
“We often talk about sedentary time as if all sitting is the same, but this study suggests that the context of sitting matters,” Trinh explained. “In this cohort, replacing passive sedentary time with mentally active sedentary time was associated with a lower risk of dementia. It is important, though, not to overstate the findings: this was an observational study, so it suggests an association, not proof of causation.”
Trinh said it’s important for doctors and patients to understand there’s a difference between passive and mentally active sedentary behaviors because this is a more practical and realistic message than simply telling people to “sit less.”
“Many adults, especially older adults, will spend part of the day sitting. The more useful question is: What are you doing while you sit? This paper is built around the idea that sedentary behaviors differ in cognitive demand, distinguishing mentally passive activities such as TV viewing from mentally active ones such as office work and similar cognitively engaging tasks. The authors also argue that using a single measure of sedentary time can miss these important differences.”
— Dung Trinh, MD
“For doctors, that means counseling can become more specific and achievable: not every seated activity carries the same implications, and encouraging cognitively engaging activities while sitting may be a more actionable step for many patients,” Trinh added.
MNT also spoke with Jasdeep S. Hundal, PsyD, ABPP-CN, director of The Center for Memory & Healthy Aging at the Hackensack Meridian Neuroscience Institute at Jersey Shore University Medical Center, and associate professor of psychiatry and neurology at Hackensack Meridian Health School of Medicine in New Jersey, about this study.
“This study adds context to an often oversimplified conversation,” Hundal, who was not involved in the study, commented.
“We already know prolonged sedentary behavior is not ideal, but this suggests the type of sedentary activity may matter, which aligns with what we already emphasize clinically, such as [reducing] passive time, particularly television or other low-engagement activities, and encouraging habits that keep patients mentally engaged, like discussing a show rather than passively watching it, can increase engagement,” he said.
For readers who may want to replace their passive, sedentary behaviors with more mentally active ones, Hundal advised starting small and, over time, making the necessary lifestyle changes rather than trying to change everything at once.
“If someone spends a significant portion of the evening watching television, replacing part of that time with reading, puzzles, strategy games, writing, learning a new skill, or more interactive activities is a practical first step. It is also helpful to break up long periods of sitting. Do not let perfection be the enemy of good. The goal is reducing prolonged passive time and replacing it with activities that are cognitively engaging and sustainable.”
— Jasdeep S. Hundal, PsyD, ABPP-CN
