Home' Trinidad and Tobago Guardian : December 5th 2015 Contents exercise might help protect against Alzheimer s or
dementia later in life. Perhaps exercise could counteract
all that TV, too. But if you re watching something
trashy and can t get off the couch, maybe just, you
know, go read a book. (Angus Chen for NPR)
body & soul
Guardian www.guardian.co.tt Saturday, December 5, 2015
When I kick back to watch a show, I tell myself
I m just going to watch one episode.
But 45 minutes later, I m watching another. And
then another. For the rest of the day. And all that
TV and chilling might be hurting my brain func-
Researchers at the University of California, San
Francisco checked in with 3,247 people for 25 years,
starting when they were young adults. Every five
years, they asked participants to estimate how much
TV they watched daily. Every two to five years, the
researchers looked at how much physical exercise
people got. At the end of the 25 years, when the par-
ticipants were in their 40s and 50s, they all took
three tests that measured their memory, focus, and
mental and physical quickness.
People who got little exercise or watched at least
three hours of TV a day did worse on tests measuring
cognitive focus and speed than those who got more
exercise or watched less TV, according to the study,
published in JAMA Psychiatry on Wednesday.
"Then people who had both low physical activity
and high TV had even worse performance. It was an
even bigger effect," says Dr Kristine Yaffe, a psychiatrist
at UCSF and senior author on the study.
Some of that loss of brain power could be because
just sitting around motionless isn t very good for us.
Scientists have known that lack of physical exercise
could be a big risk factor in cognitive decline, says
Marcus Richards, a psychologist at the University
College London who was not involved in the study.
"But we don t know much about sedentary behavior
[and cognition] right now," he says. If people who
spend a lot of time binge-watching TV are doing so
half-comatose on a cushion, they might not be doing
their brain any favours.
Or perhaps it s something about TV watching itself,
Yaffe thinks. "Is it because by watching a lot of TV,
you re not challenging your brain?"
Yaffe s team didn t look at whether people were
watching smart, intellectual documentaries or mind-
numbing shows like The Bachelor or The Apprentice
for over three hours daily.
"Some TV shows can be cognitively stimulating,
and there s some evidence that cognitively stimulating
activities can be protective and beneficial," says Margie
Lachman, a psychologist at Brandeis University who
was not involved in the study. Perhaps some content
is better for your brain than others.
The study wasn t able to test the participant s cog-
nitive function when they were young adults, either.
It s possible that people who score lower on the tests
are more likely to watch more TV than the other way
"People with low cognitive function perhaps are
less likely to engage in physical activity, and maybe
more likely to engage in sedentary behaviours," Lach-
man says. Similarly, other studies have found that
binge-watching TV is more common among depressed
people, but that doesn t mean it causes depression.
In either case, Yaffe says the decline in people s
cognition speed and focus, while significant, wasn t
huge---certainly not enough to affect someone s daily
life. "The question is what does it mean if you re 50
and you ve got these slight changes? Does it mean
you re on a path to greater changes down the line
or does not make a difference? I don t think we really
know the answer to that."
But Richards says it s reasonable to think the gap
in cognitive function between high-volume TV watch-
ers and infrequent watchers might widen over the
years. For some, the early decline in cognitive func-
tioning could become serious later in life. "As the
cohort ages, you would expect that rate of decline
to become rather more rapid, with some people mov-
ing into clinical outcomes like dementia," he says.
In the past, researchers have noticed that physical
More than three hours a day could mean brain fade by middle age. PHOTO: CORBIS
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Too much TV could
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