Spending too many hours watching television during middle age may be associated with brain changes related to Alzheimer’s. The discovery comes from research that followed 1,712 adults for approximately 24 years.
The work also revealed that a sedentary lifestyle should not be analyzed only by the time a person spends sitting. The activity carried out during this period can have a different influence on brain health.
Study followed adults for more than two decades
Published in the magazine Alzheimer’s & Dementiathe study used data from ARIC (Atherosclerosis Risk in Communities), an American survey that monitors factors linked to aging and cardiovascular diseases.
Participants were, on average, 53 years old when they answered questions about their sedentary habits, between 1987 and 1989. About 24 years later, between 2011 and 2013, they underwent MRI scans to evaluate brain structures.
The investigation compared two behaviors:
- Frequency of watching television during free time;
- Time spent sitting during professional activities.
Those who reported watching TV very frequently showed differences in brain regions affected at the beginning of the process associated with Alzheimer’s.
Among the main findings were:
- Greater volume of white matter hyperintensities, a marker linked to changes in small cerebral vessels;
- Less volume of the frontal and occipital regions;
- Reduction in areas considered signatures of Alzheimer’s disease.
White matter hyperintensities are changes identified on imaging tests and associated with cognitive decline and an increased risk of dementia.
What happens while we’re sitting matters
One of the most curious results was that different forms of sedentary lifestyle showed different relationships with brain structure.
Watching television frequently appeared associated with less favorable indicators, while remaining seated while working showed different associations, including lower volume of white matter hyperintensities and greater volume of some brain regions.
For the authors, a possible explanation lies in the level of mental stimulation involved. Professional activities may require more concentration, reasoning and decision-making than watching television.
We often encourage the public not to spend too much time sitting, but experts may want to expand this recommendation to cover activities performed while sitting, as these appear to have distinct impacts on brain health.
Natan Feter, corresponding author of the study and postdoctoral researcher at USC Dornsife, in a note.
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David Raichlen, professor of Biological Sciences and Anthropology at USC Dornsife and one of the lead authors of the research, highlighted that sitting time doesn’t tell the whole story.
Results remained even among active people
The analysis considered factors such as age, sex, education, hypertension, diabetes, body mass index (BMI), physical activity, smoking and alcohol consumption.
Even after these adjustments, the relationship between frequent television viewing and changes in brain structure remained.
The research also found differences between the sexes. Among men, the habit was associated with reductions in several brain regions, including frontal, temporal, occipital, parietal and deep regions of the brain. Among women, no significant associations were identified in most of the areas evaluated.
The authors highlight limitations, such as the fact that the time spent watching television was reported by the participants themselves and the absence of brain exams at the beginning of the follow-up.
The conclusion is that measuring just how many hours a person sits may not be enough. The type of activity performed during this period also seems to be an important variable in understanding the relationship between a sedentary lifestyle and brain health.
Source: www.olhardigital.com.br
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