A Brisk Walk Can Turn Back the Clock
MODERATE AEROBIC EXERCISE LINKED TO IMPROVED MEMORY
Researchers have found an association between moderate levels of aerobic exercise and increased size of the hippocampus, an area of the brain involved in memory. This is the first study to focus on older adults who already have experienced some decrease in the size of the hippocampus, believed to be the (potentially-inevitable) cause of memory loss with age.
Some of the 120 sedentary adults were placed on a routine of brisk, 40-minute walks three times a week, while others did stretching and toning exercises. In those who walked, hippocampus size increased almost 2%; memory function improved; levels of brain-derived neurotrophic factor (a biomarker for learning and memory) increased; and scores on spatial memory tests were higher. (Spatial memory records information about a person’s immediate environment and geographical orientation.)
It is important to note that the effect was found only with aerobic exercise; and that only moderate exercise levels were sufficient to produce this effect.
This study was released January 31, 2011 but will not appear in print until a future issue of the journal, Proceedings of the National Academy of Sciences. It is available online now at http://bit.ly/hhnodP.
Dim Light at Night Linked to Depression
DIM LIGHT AT NIGHT LINKED TO DEPRESSION
Researchers have found that exposure to even a dim light while sleeping is sufficient to cause physical changes in an area of the brain that is associated with clinical depression. This is the first study to find that light at night, by itself, leads to a lower density of dendritic spines in the hippocampus region of the brain. (Dendritic spines are hair-like growths on brain cells, which are used to send chemical messages from one cell to another.)
One previous study found that bright light during sleep periods causes depressive symptoms and another found light at night is linked to weight gain. But the new study focused on the dim light of 5 lux, which is similar to a switched-on television in an otherwise darkened room. The researchers speculate that exposure to light during sleep suppresses secretion of melatonin, the hormone that lets the body know when it is nighttime. This study was presented November 17, 2010 in San Diego at the annual meeting of the Society for Neuroscience. It has not yet been published in a journal and is not yet available online.
Vitamin D & Mental Agility
Cognitive performance is much improved among the elderly who are not deficient in vitamin D, and vitamin D deficiency may be common among shut-in seniors due to limited access to sunshine and other factors, according to a new study.
More than 1,000 study participants who were receiving home care were assessed for vitamin D status. Only 35 percent of participants had sufficient vitamin D levels and this group scored higher on cognitive performance tests than those who were deficient or insufficient in vitamin D. Pathways for vitamin D have been identified in the hippocampus and cerebellum areas of the brain; these are regions associated with planning, processing new information and forming new memories, suggesting vitamin D is important to the cognitive process and for independent senior living.
The study was released by the journal titled, Journals of Gerontology, Series A, Biological Sciences and Medical Sciences, in a summary format. But it is available in full-text format at: http://bit.ly/d2FtYY.