Almost 50 percent of North Americans over 85 and 13 percent of those over 65 suffer from Alzheimer's disease (Alzheimer's Assoc Facts and Figures, 2018). We know that you lose brain cells as you age, and scientists used to think that you could not make new brain cells. However, an exciting new study from Columbia University suggests that you can make new brain cells as you age, and that loss of brain function may be caused by lack of adequate blood flow and nourishment of brain cells (Cell Stem Cell, April 5, 2018;22(4):589–599).
The authors found that all age groups, from young to old, have the same number of neural progenitor cells and immature neurons that make new nerve cells in the hippocampus, the part of the brain that governs memory. Contrary to a previous study that showed no new nerve growth with aging (Nature, March 2018), this new study suggests that the brains of older people have progressive loss of new blood vessels with aging and with that, the loss of ability of brain cells to connect with each other. If lack of blood flow to brain cells can cause dementia, its prevention should include exercise -- the most effective way to increase growth of new blood vessels. Many previous studies show that exercise:
• increases blood flow to the brain, and
• reduces risk for diabetes and obesity which can damage the brain. This new study suggests that anything that increases blood flow to the brain may stimulate growth of new blood vessels and brain cells.
Studies Showing that Exercise Reduces Risk for Dementia A study of 1,462 women, ages 38 to 60, followed for 44 years, showed that those who exercised regularly were one tenth as likely to suffer dementia with aging as those who did not exercise (Neurology, March 14, 2018). In another study, 6500 older people wore exercise trackers. After three years, those who exercised regularly had a 36 percent lower risk of memory loss as well as better memory and executive function (Medicine & Science in Sports & Exercise, January 2017;49(1):47–53).
A third study of 81 older adults used VO2 max, a test of maximal ability to take in and use oxygen, to give a dependable measure of fitness. Those who were less fit had an increased rate of dementia and of losing the white matter in their brains that helps them to retain memory and make wise decisions (Journal of Alzheimer's Disease, Dec 19, 2017;61(2):729-739). An earlier review of hundreds of articles showed that older people who exercise have far less loss of brain function with aging, less brain blood vessel damage, larger hippocampal brain size for better memory, less loss of brain tissue with aging, better spatial memory, better communication between brain nerves and improved ability to learn new facts (Mayo Clin Proc, 2011 Sep; 86(9): 876–884).
My Recommendations If you don't already engage in a regular exercise program, check with your doctor and then try to start one as soon as possible. See How to Start an Exercise Program
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