Is your brain paying the price for your TV viewing habits?

What’s going on with your TV watching lately?  Are you glued to Line of Duty, with your finger poised and ready to hit the “next episode” button? 

Then join the party.

Our TV viewing has skyrocketed this past year, to an average of 6.5 hours a day in lockdown, as it provided a few crumbs of comfort when everything else was cancelled. But now it could be time to wean yourself off.

Our mothers always told us that too much TV would rot our brains and it seems they were right, as three new studies would seem to confirm.

The research suggests that excessive TV watching in midlife is linked to cognitive decline in later life, with those who reported watching moderate-to-high volumes of TV showing a 6.9 per cent greater drop in cognitive processing over 15 years, as measured by their ability to complete cognitive tasks like reading, learning and memory recall. 

Too much TV might even shrink our brains, with another study showing that every extra hour of TV watched daily, between the ages of 30 and 50, was linked to a 0.5 per cent reduction in grey matter. 

This preliminary research was presented at the American Heart Association’s Epidemiology, Prevention, Lifestyle and Cardiometabolic health conference online.

Our habit of excessive TV viewing could also be adding to the already worrying levels of dementia, say the experts. Worldwide, more than seven million new dementia cases are diagnosed annually. By 2050, the prevalence of dementia is expected to increase by 116 per cent in high-income countries and 264 per cent in low-income countries.

Though it’s not yet possible to prove a causal link, a growing body of research is ringing alarm bells over the link between dementia and our skyrocketing TV viewing habits.

“Recent research has demonstrated that television watching can cause changes in brain structure, specifically in the parts responsible for learning and memory,” explains Dr Dorina Cadar, a research psychologist at UCL’s Behavioural Science and Health department, who is conducting studies into dementia. “So it’s not surprising to find that over time, memory, processing speed and other aspects of cognition can decline among those who watch a lot of television.”

Scientists believe that it’s not only our TV watching that’s the issue, but the fact that we’re simply spending too many hours curled up on the sofa.

“Our brains are bathed in cerebrospinal fluid (CSF) which is literally the food for the brain as it is teeming with growth factors that nourish neurones,” explains Dr Cadar. “In normal ageing growth factors are less abundant and, as a result, the neurones can become sluggish and even die. But if we get up and move about, the brain produces chemicals and can spray itself with nutrients, not dopamine and serotonin that you might have heard of, but something called Brain Derived Neurotrophic Factors, or BDNF. My suggestion is to stand up and start moving. Simply doing this will switch on the ‘pharmacy’ at deepest roots of our brains.”

But is all TV watching equally damaging, or might a documentary or an episode of University Challenge actually increase our intellectual prowess?

“Yes, the programs from which you learn something will always be more beneficial for the brain,” says Dr Cadar. “But at the same time, if Googlebox is your favourite programme, it might be more relaxing and better for your psychological wellbeing, especially if you watch it with your family or friends.”  Conversely, staying glued to the news, as many of us have this past year, could increase our chances of depression, she says, which could damage our ability to solve problems and focus.

But what if we’ve already been on a Netflix ultra-marathon throughout the pandemic? Is there any way to recoup that lost grey matter?

Fortunately, a growing number of studies suggest that we can not only stem the rot but also grow new brain cells, thus improving our brainpower, until our late 80s.

“We used to think ‘use it or lose it’ and that brain cells we don't use will wither,” says Dr Cadar. “Now we know that use it and you'll also produce it, and that's the lesson for people.”

So what are the best things to build up our brains when we’re not watching telly?

First, move. “Aim for a combination of aerobic exercises, such as brisk walking or any activity which makes you a little breathless,” says Dr Cadar, “plus strength or resistance training, that’s the most beneficial for brain skills. Aerobic exercise also protects the brain by keeping blood vessels healthy, reducing the risk of heart attack, stroke and vascular dementia.” 

Second: read. Reading in midlife, and beyond, is associated with a reduced risk of dementia, particularly in women, according to UCL research published in the Journal of Alzheimer’s Disease. “It’s important to put new content into our memory banks,” says Dr Cadar. “It may be a book, a magazine, or a podcast, but you’re adding layers of knowledge and emotion.” Pick books or articles that challenge your vocabulary, look up new words and use them five times to assimilate them into your own knowledge bank.

Third, learn a new skill or language. “Memory and language sit close together in the brain,” says Dr Cadar, “which is why anything that exercises or stretches our language skills is an excellent brain workout.”

Being bilingual has a protective effect against the symptoms of dementia, but trying to learn another language will increase your odds of staying sharp, explains Dr Cadar, and learning a musical instrument has the same effect. The same goes for puzzles like Sudoku.

“Neuroplasticity is the way in which our brains can adapt, often enabling amazing recovery after injury, and any different, new tasks or experiences that nurture that are good for brain health,” explains Dr Cadar. She suggests using your non-dominant hand to operate your phone, eat or write. “This forces the movement areas in your brain to recruit idle neurones to the task,”  she says. “Your brain cells are very different from your heart cells. If a part of your heart dies because of a heart attack, it cannot come back, but if part of your brain dies, say for a small stroke or an injury, it can come back, it can repurpose – that’s neuroplasticity, and we should really treasure more this magical aspect of our brain.”

Finally, meet a friend or six. Staying connected socially in your 50s and 60s predicts a lower risk of developing dementia later on, according to a UCL study published in the British Journal of Psychiatry.

But given that our TV habit is unlikely to go away, how much is safe for our brains before the rot sets in?

Dr Cadar suggests a maximum of two hours per day, as more than three hours a day is associated with cognitive decline, in some studies. Though the occasional binge is acceptable, she says.

“I would say if a few hours of binge-watching provides a form of relaxation, that in itself is a good thing,” she says, “so long it’s not becoming a habit.”

And if you must binge, I recommend the stylish French Netflix drama, Call My Agent. You can always switch off the subtitles to give your grey matter a workout.