Heavy TV watching associated with smaller brain structures, study finds - Medical Xpress

What the report says

Medical Xpress reported on July 19, 2026, that a new study links frequent television viewing in midlife with smaller brain structures and signs of poorer brain health later in life. The research, published in Alzheimer’s & Dementia and provided by the University of Southern California, examined whether different sedentary activities have different associations with brain structure, rather than treating all sitting time as the same.

According to the report, researchers analyzed about 1,700 adults in the Atherosclerosis Risk in Communities Study who were enrolled between 1987 and 1989 at an average age of 53. Participants reported how often they watched television during leisure time and how much they sat during work. More than 20 years later, brain MRI scans showed that people who said they watched TV “very often” had smaller volumes in memory-related regions, reduced frontal and occipital lobe volumes, and more white matter hyperintensities, which are commonly associated with small vessel disease, aging, cognitive decline and dementia risk.

The authors said the findings remained after accounting for factors including physical activity, diabetes, body mass index, smoking and alcohol use. They also found that occupational sitting did not show the same pattern; in some measures, people who sat more at work had brain features associated with better health, possibly reflecting more mentally demanding activities. The report noted that the effects appeared more pronounced in men.

The study does not prove that watching television causes brain shrinkage. Medical Xpress noted limitations including self-reported TV habits and the absence of baseline MRI scans. Still, the findings may add nuance to public health advice by suggesting that the type of sedentary activity, not only the amount of sitting, could matter for long-term brain health.