TV binges really do shrink your brain
(but only if you’re middle-aged)
TV is often accused of dumbing us down – but the brains of middleaged viewers who binge-watch really can shrink.
American researchers who studied scans of those who spent more than two hours a day in front of their televisions found lower volumes of grey matter – which is typically an indication of worse brain performance.
It’s certainly bad news for British TV fans who rack up high viewing hours on hit shows such as Gogglebox. Ofcom revealed last month that the average Briton spent five hours 40 minutes watching TV or online videos daily in 2020.
According to the US research, every extra hour of average daily TV time between the ages of 30 and 50 was linked to a 0.5 per cent reduction in grey-matter volume. Study leader Dr Ryan Dougherty, from Johns Hopkins Bloomberg School of Public Health in Baltimore, said: ‘In the context of cognitive and brain health, not all sedentary behaviours are equal.
‘Non-stimulating sedentary activities such as television viewing are linked to greater risk of developing cognitive impairment, whereas cognitively stimulating sedentary activities (eg reading, computer and board games) are associated with maintained cognition and reduced likelihood of dementia.’
His team examined the link between grey-matter volume and viewing habits of 599 adults from four major American cities between 1990 and 2011. Volunteers were asked about their viewing habits and were interviewed every five years. On average, participants watched two-and-a-half hours of TV daily over the two decades.
MRI scans found long-term viewing reduced volume in the frontal cortex and entorhinal cortex – followed by total grey-matter volume in middle age.
‘Because brain atrophy becomes apparent in midlife, our findings raise the question if reducing television viewing (or other nonsedentary behaviours) could preserve total grey matter volume and protect against future cognitive decline,’ wrote Dr Dougherty in a paper published in the scientific journal Brain Imaging And Behavior.
‘Our findings suggest that television viewing, independent of physical activity, plays a role in brain, cognitive and overall health.’ He said the results underlined the need to identify behaviours, such as bingeing on box sets, that can be changed before damage to the ability to think is impaired. ‘This is an important finding as it is now well accepted that the neurobiology of dementia, including brain atrophy, begins during midlife, a period where modifiable behaviours, such as excessive TV viewing, can be targeted and reduced,’ he said.