Adults aged 40 to 60 who watch excessive amounts of TV were linked in a new study to smaller brain structures later in life.
Researchers said the concern centers on passive screen time, suggesting that replacing some television viewing with mentally stimulating activities and regular movement may better support brain health.
The findings do not prove that changing those habits will prevent cognitive decline, and the researchers said further studies are needed to test whether the link is causal.
The report adds to growing evidence that not all sedentary behavior carries the same risk, with passive activities such as TV watching and scrolling drawing increasing scrutiny.