One change to your TV-watching routine may keep you healthier longer

In Roald Dahl’s book Matilda, a telekinetic child genius who loves school and reading resists her family’s habit of eating in front of the television. It is one of her first acts of defiance and a sign that she is different. She asks instead to read a book in her room and earns a sharp rebuke from her father:

“I would mind!” he snapped. “Supper is a family gathering and no one leaves the table till it’s over!”

“But we’re not at the table,” Matilda said. “We never are. We’re always eating off our knees and watching the telly.”

“What’s wrong with watching the telly, may I ask?” the father said. His voice had suddenly become soft and dangerous.

Dahl might have had a bit of a personal vendetta against television (just look at this poem), but in truth, he may have been on to something: There might, indeed, be quite a bit wrong with watching too much TV.

In preliminary findings presented at the American Heart Association’s 2021 Epidemiology, Prevention, Lifestyle & Cardiometabolic Health Conference, a set of three separate studies found evidence to suggest that spending an inordinate amount of time watching television does appear to affect brain health. The studies — which have not yet been published in peer-reviewed journals — link excessive television-watching in later life with declining cognitive performance and less gray matter in the brain.

The exact nature of the association is not clear, but one theory is that watching TV just doesn’t give the brain enough of a workout.

“There’s not a lot of thought that goes into watching television,” Kelley Pettee Gabriel tells Inverse. “Maybe if you're watching Jeopardy, that’s another story. But it’s a very cognitively passive activity.”

Gabriel is the lead author of one of the studies and a co-author on one of the others. She is also a professor in the department of epidemiology at the University of Alabama, Birmingham.

SCIENCE IN ACTION — The new analyses take an in-depth look at a subset of people who participated in three long-term studies. These studies involved collecting data for years, beginning in the late 80s. Two of the studies had asked participants who were in their middle age if they watched TV very little (low), sometimes (moderate), or very often (high). The third involved researchers asking participants to track how many hours each day they spent watching TV.

Together, they found that:

1. In one study involving 10,700 participants aged 59 on average, people who reported “high” or “moderate” levels of TV-watching earlier in life also showed signs of faster cognitive decline in later life than did those who watched TV only seldomtimes.
2. In another study of 1,601 participants aged 76 on average, those who reported watching TV a lot earlier in life also tended to have less gray matter in certain brain areas in later life based on MRI scans taken between 2011 and 2013.
3. In the third study, 599 participants attended two clinic visits — one when they were aged around 30 years old, and another when they were around 50 years old. In these people, watching above-average hours of TV (the average was 2.5 hours) was associated with less gray matter in some parts of the brain.

HOW THIS AFFECTS LONGEVITY — Preliminary as they are, the findings suggest that choosing to watch less television may help to ward off some of the undesirable brain effects of old age, specifically namely, declines in cognitive function. In these studies, the researchers pay special attention to “working memory, language, and executive function.” It may also increase the brain’s resilience to old age and preserve brain matter.

In the brain, there is both gray matter and white matter. Gray matter has a higher concentration of neurons. It allows us to regulate our muscles, memories, and emotions. Some diseases associated with both age and cognitive impairment, like Alzheimer’s and Parkinson’s, are characterized by damage to gray matter.

LONGEVITY HACKS is a regular series from Inverse on the science-backed strategies to live better, healthier, and longer without medicine. Get more in our Hacks index.

Notably, the research focuses on television watching, not just any sedentary activity. Another one of the studies’ authors, Johns Hopkins University postdoctoral student Ryan Dougherty, summed it up in a press release:

“In the context of cognitive and brain health, not all sedentary behaviors are equal.”

“Cognitively stimulating sedentary activities (e.g., reading, computer, and board games) are associated with maintained cognition and reduced likelihood of dementia,” he added.

So it may be that video games and reading — but not television — actually help rather than hinder the brain as it ages. Too much TV, conversely, may create problems down the road.

WHY IT’S A HACK — Scientists have known for a long time that exercise is good for your health and boosts your chances of living longer, healthier lives. But the opposite of exercise — sedentary behaviors, like watching TV for hours every day — are coming into the scientific spotlight, too. These aren’t the first studies to suggest TV may rot your brain. A 2019 study in Science Reports found that watching television for more than 3.5 hours a day was linked to worse verbal memory in older adults.

Teasing out what the mechanisms driving these tenuous associations are may inspire researchers for years to come.

“Now that we have this improved understanding of sedentary behaviors, and that they might have different associations with health and disease, we’re starting to look at these questions,” Gabriel says.

Last year, the WHO released new physical activity guidelines that specifically provide information on sedentary behavior and the attendant health risks, including poorer heart health, less “pro-social” behavior, and worse sleep.

But as far as sedentary behavior’s effects on the brain, the research is still preliminary. Gabriel says it’s possible that with a certain level of exercise, the time we spend in sedentary activities may be tempered. But ultimately, she cautions, robust evidence to show this reverse-engineering may be possible “hasn't been done with brain health.”

“But it has been done with other outcomes, like all-cause mortality and cardiovascular disease,” she says. “This area’s super, super new.”

The studies also focused on middle to old age, when habits may be harder to break. For young Netflix binge-watchers today, the potential brain risks later in life that these studies suggest might be enough to get you up off the sofa — or at least watch one less episode.

HACK SCORE OUT OF 10 — 📺📺📺📺📺📺📺/10 (No TV ➡️ no brain rot)