Multiple studies have shown that physical exercise not only protects memory and cognitive function, but also increases the size of the brain’s hippocampus, a medial temporal lobe region important for creating and retrieving memories.

Our UCLA research group explored the impact of sitting on the brain’s hippocampal thickness. We recruited 35 volunteers ages 45 to 75, and recorded how many hours they spent each day sitting during the previous week.

We then performed high-resolution MRI scans to obtain measures of the medial temporal lobe where new memories are formed.

We found that the number of hours of sedentary behavior predicted thinning of the lobe. Even high levels of physical activity were not sufficient to offset the thinning effects of extensive sitting.

Although further research is needed to prove that extensive sitting makes brains thinner, the study suggests that people with desk jobs should get up, stretch, and move around at regular intervals.

Other options are standing desks or treadmill desks.