Watching too much TV in midlife may shrink the brain - ScienceDaily

What the report says

ScienceDaily, citing materials from the University of Southern California, reported that a study published in Alzheimer’s & Dementia found an association between very frequent television watching in midlife and less favorable brain structure decades later. The research drew on about 1,700 adults in the long-running U.S. Atherosclerosis Risk in Communities study, who were around age 53 when they reported leisure-time TV habits between 1987 and 1989 and later underwent brain MRI scans more than 20 years afterward.

According to the report, participants who said they watched television “very often” later had smaller volumes in brain areas related to memory, as well as reduced frontal and occipital lobe volumes. They also showed more white matter hyperintensities, MRI markers that can reflect small blood vessel disease in the brain and are associated in other research with cognitive decline and dementia risk. The associations remained after researchers adjusted for factors including physical activity, diabetes, body mass index, smoking and alcohol use.

The findings do not prove that TV viewing caused the brain differences. ScienceDaily noted limitations including reliance on self-reported TV habits and the lack of MRI scans at the start of the study, which makes it harder to track individual brain changes over time. The study also found that other sedentary behavior did not show the same pattern: people who spent more of the workday sitting tended to have brain measures that looked healthier, possibly because seated work can involve more mental engagement.

Researchers said the results suggest public health advice about sedentary time may need to distinguish between passive and cognitively demanding activities. The report also noted that the observed links appeared more pronounced in men, though further study is needed to understand any sex-specific differences.