Get Up & Move! Your Brain May Be Shrinking
What: UCLA researchers looked at the relationship between volume in the brain’s medial temporal lobe (MTL), an area closely associated with memory, physical activity and sedentary behavior in older adults. 35 cognitively healthy subjects ranging in age from 45-75 years were assessed using functional MRI and a self-report questionnaire of physical and sedentary activity (i.e., hours spent sitting each day). They found that the more hours folks reported sitting, the smaller the size of their MTL. In addition, this link did not seem to be mediated by level of physical activity, meaning that exercise didn’t counteract the observed shrinkage.
Why This Matters: You may have heard that sitting is the new smoking; It may just also be the new brain buster as well. What is most surprising from this study, however, is the seeming lack of impact that physical activity had in modifying the influence of sedentary behavior on brain volume. This finding in particular is a bit to the left field of a greater body of research that suggests regular aerobic exercise strongly supports neuroplasticity and brain volume across all ages.
The Takeaway: Should we worry that those hours sitting at our desks and in our cars have irreversibly shrunk our brains? Given the small sample used in this study of only 35 people, we can probably relax and see what larger studies may show. However, this does join the mounting evidence for the many ways in which sitting down for hours at end may be bad for our health. So I did stand up to write this update!
Siddarth, P et al. Sedentary behavior associated with reduced medial temporal lobe thickness in middle-aged and older adults. PLOS One Published April 12 2018. https://www.ncbi.nlm.nih.gov/pubmed/29649304