Daily Brain Snack: Sitting Shrinks Your Brain
Sitting time is what shrinks your brain even in those who exercise
We’ve known that sitting is bad for you for a long time haven’t we?
Indeed, one of the first studies to report on the relationship of sitting and activity on health was into bus drivers and bus conductors in England (back when there was even such a thing as a bus conductor).
That study saw noticeable differences in health outcomes, cardiovascular health originally, between the bus drivers who spent their day sitting and bus conductors who were more physically active.
But the question is, is it exercise that boosts health, or sitting that reduces health, or a combination of both?
I imagine a combination of both.
Well, this is what Marissa Gogniat et al. of Vanderbilt University studied over a 7-year period. They measured activity of 404 adults over 50 over a week in detail with a fitness tracker and then followed them over a 7-year period when they followed up with cognitive tests and brain scans.
And what were the results?
Actually quite clear. Sitting is what contributes to decreased cognitive processing speed, lower memory ability, and also a reduction in volume of the hippocampus, a brain region key for memory and navigation.
Oh, and activity doesn’t help?
Well, yes, as we know, and I have reported many times that activity and exercise does many good things for the brain and body but the key take away here is that sedentary time is bad for you.
Those who exercised but also had high sedentary time showed worse outcomes than those who exercised and had less sedentary time.
Of note, and logical, is that those who had a genetic predisposition to Alzehimer’s (having the APOE-ε4 gene) also showed worse outcomes (but again sedentary time did magnify this).
So sitting is bad for your brain!
And health.
What about many of us who sit in the office for long periods?
Yes, many of us, including myself, may sit for long periods at the computer. But the key is how often do you break this up. Just breaking up this sitting with short periods of movement and activity already makes a big and critical difference.:
Regular short breaks with movement e.g. getting a coffee or tea
Regular short walks, as short as five minutes
Add some micro exercises: a quick stretch or a few squats
Fortunately I do a lot of the above - but I am also conscious to make sure I move a lot also.
So make sure you break up sitting with regular movement
Precisely. Your brain will thank you for it. And it may be easier than you think and the benefits are substantial, particularly over time.
Reference
Marissa A. Gogniat, Omair A. Khan, Judy Li, et al., Omair A. Khan, Judy Li, et al.
Increased sedentary behavior is associated with neurodegeneration and worse cognition in older adults over a 7-year period despite high levels of physical activity
Alzheimer’s and Dementia, 2025
https://doi.org/10.1002/alz.70157