According to research at UCLA, changes in a section of the brain that is critical for memory are associated with sitting too much. The study involved people ages 45 to 75. An MRI of each person provided a look at the region of the brain involved with the formation of new memories. The study did not conclude that sitting causes thinner brain structures, but that it is associated with having thinner regions.
Growing evidence from research suggests that physical exercise is a promising intervention for delaying the onset of dementia and Alzheimer’s disease.
It is recommended to move for three minutes every 30 minutes to improve both physical and mental health. Some of the simple ways to encourage movement are:
 Siddarth P, Burggren AC, Eyre HA, Small GW, Merrill DA (2018) Sedentary behavior associated with reduced medial temporal lobe thickness in middle-aged and older adults. PLoS ONE 13(4): e0195549. https://doi.org/10.1371/journal.pone.0195549
 Beckett MW, Ardern CI, Rotondi M. A meta-analysis of prospective studies on the role of physical activity and the prevention of Alzheimer’s disease in older adults. BMC Geriatr. 2015;15:1–7