Passive sitting and 'brain rot' may increase dementia risk, study warns
A new study has found that spending too much time on mentally passive activities while sitting down may raise the risk of dementia. Researchers tracked over 20,000 Swedish adults and discovered that swapping passive habits for active mental tasks could lower that risk. The findings also highlight how combining movement with brain-stimulating behaviour might offer even greater protection.
The study, which followed 20,811 adults, showed that those who spent more time on passive activities—like watching TV or scrolling through short videos—had a higher chance of developing dementia later in life. Experts have warned that excessive consumption of fast-paced, short-form content could contribute to cognitive decline, sometimes called 'brain rot'.
However, the research also revealed ways to reduce this risk. Replacing just one hour of passive sitting with mentally active tasks, such as reading or puzzles, lowered dementia risk by 7%. Even adding an extra hour of mentally engaging behaviour while sedentary cut the risk by 4%. The most significant benefit came from pairing physical activity with specific mental exercises. Computer-based speed training, designed to improve processing speed, proved particularly effective. When combined with light movement like walking, this approach reduced dementia risk by 25%. Overall, blending physical and active mental behaviour decreased the risk by 11%. The study had some limitations, though. It relied on self-reported data and did not account for smartphone or social media use, which could also influence cognitive health.
The findings suggest that both the type of mental activity and movement play a role in long-term brain health. While sitting for long periods harms the body and mind, small changes—like choosing active mental tasks over passive ones—could make a measurable difference. Researchers stress that even minor adjustments in daily habits may help lower dementia risk over time.
