Sitting Is Forgetting, New Report Claims

We’ve been worried for a long time that all this sitting is making us fatter. But now researchers have added a new twist to our fears: too much chair time is actually making our brains thinner.

In a new study, researchers have found that the brain’s medial temporal lobe — associated with learning and memory — loses volume in association with prolonged sitting. Shrinkage in this portion of the brain is likely a contributing factor to dementia and Alzheimer’s, so this is definitely an area of concern.

The study surveyed 35 cognitively healthy people between the ages of 45 and 75. Volunteers were asked about their physical activity habits, and had their brains scanned with an MRI machine. Researchers then compared how participant activity and sitting habits corresponded to thickness levels of critical brain structures.

With reported average sitting times ranging from three to 15 hours per day, researchers were able to determine that (adjusting for subject age) each hour of additional average daily sitting was associated with a 2% decrease in medial temporal lobe thickness. And so, for example, a person who sits for 15 hours a day would have a medial temporal lobe that’s 10% thinner than a person of the same age who sits for 10 hours a day.

Of further concern, the study found no correlation between exercise habits and brain thickness. And so even people who exercised regularly, but then spent a lot of additional time seated, did not escape the thinning brain. This went against other studies that have previously found greater brain volume and cognitive performance in people who exercise regularly.

“We need larger samples and better ways to measure patterns of sedentary behavior,” study leader Prabha Siddarth told the Los Angeles Times. “But if you’re sitting for long periods of time, it seems that that factor — not physical activity — becomes the more harmful or more significant measure of your fitness. Even for people who are physically active, sitting a lot seems to be bad for your brain.”

And so prolonged sitting can now be associated with brain atrophy in addition to sitting’s previously confirmed relationships with heart disease, diabetes, and mortality.

The antidote, or course, is to get out of your chair. Exercise is as valuable as ever, but in addition to that pre- or post-work workout, we need to consciously untether ourselves from our desks during the day. Find a way to get up occasionally and move around. Set an alarm for an hourly reminder march around the office. Take a walk at lunch. Don’t skip those 15-minute bathroom breaks, even if you’re not using the bathroom. Siddarth suggests dancing with your headphones on.

If your bosses and co-workers look at you funny, tell them it’s all about keeping your brain sharp for the job.