30 April 2018

Here’s another reason why you shouldn't sit so much

According to a new study, too much sitting may have an unhealthy effect on a part of the brain involved with memory.

There's been lots of research into how too many hours lounging on chairs and sofas can harm the heart. Now, researchers say all that sitting might be bad for your brain, too.

A new study found that too much time spent sitting was correlated with an unhealthy "thinning" of tissue in a key brain area tied to memory.

The findings were reported in the journal PLOS One.

Formation of new memories affected

And it appears that the link isn't simply due to the fact that people who sit for hours each day aren't exercising – there was something about the act of sitting itself that seemed to be key, the researchers said.

"We found that sedentary behaviour, but not [levels of] physical activity, was associated with less thickness of the medial temporal lobe," a brain region that's crucial to the formation of new memories, explained a team led by Prabha Siddarth.

Siddarth is a biostatistician at the University of California, Los Angeles' Semel Institute of Neuroscience and Human Behavior.

Thinning of specific brain region

One brain specialist called the research early, but "intriguing".

While the study can't prove that sitting helped cause the brain tissue thinning, the research "bears further exploration," said Dr Marc Gordon, chair of neurology at Zucker Hillside Hospital in Glen Oaks, New York.

In the study, Siddarth's group asked 35 people, aged 45 to 75, about their physical activity levels and the average amount of time they spent sitting each day during the previous week. Each participant also underwent a scan of their medial temporal lobe.

Study participants who spent a lot of time sitting were more likely to have thinning of this brain region, the investigators found. And that included even those people who had relatively high levels of physical activity when they weren't sitting.

As Dr Gordon noted, however, "not all sitting behaviour is necessarily equal, and what people are doing while they are seated may have different effects [on brain health]".

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