About 22 percent of North Americans ages 85-89 and 33 percent of those over 90 suffer some degree of dementia (JAMA Neurol, 2022;79(12):1242-1249). The risk for dementia can be reduced significantly by exercising and lowering high blood sugar levels, maintaining a healthful weight, and avoiding smoking (Lancet, Feb 1, 2022;7(2):e93-e94). Two recent studies show that exercise may be even more important in reducing Alzheimer’s disease risk:
• A study of 21,982 patients with Alzheimer’s disease and 41,944 controls without Alzheimer’s disease were classified by their genetic ability to grow larger muscles. Those with larger muscles had a significantly greater cognitive performance (memory) and were significantly less likely to develop Alzheimer’s disease (Brit Med J, June 2023;2:e000354). Many studies show that obesity is associated with a markedly increased risk for Alzheimer’s disease, by increasing risk for inflammation, insulin resistance, and higher levels in fat tissue of the protein harmful to brain health, amyloid beta. This study shows that having large muscles may be even more important in helping to prevent Alzheimer’s disease.
• Starting an exercise program helped a group of previously-sedentary seniors to improve brain memory and reasoning (Journal of Alzheimer’s Disease Reports, May 12, 2023;7(1): 399-413). The researchers used functional magnetic resonance imaging to show improvement in the 33 volunteers, 70-80 years old, half of whom suffered from “mild cognitive impairment”, a loss of memory and reasoning that often precedes Alzheimer’s disease.
Exercise Helps You Live Longer
The Physical Activity Guidelines for North Americans recommend a minimum of 150-300 minutes per week of moderate physical activity, such as walking, weightlifting and lower-intensity exercise; 75-150 minutes per week of vigorous physical activity, such running, bicycling or swimming; or an equivalent combination of both (U.S. Department of Health and Human Services, 2nd edition, 2018). The Nurses’ Health Study and The Health Professionals Follow-Up Study (116,221 men and women followed for 30 years) found that men and women who exercise more than these recommended amounts live longer (Circulation, July 25, 2022;146(7):523-534). Those who exercised for the recommended 150–300 minutes per week or more gained a 19-25 percent lower risk of death from all causes. Those who reported two times the recommended minimum exercise time showed an additional 2-4 percent reduction in death rate, and those who exercised four times the minimum recommended time added 3-13 percent reduction.
How Exercise Might Help to Prevent Dementia
Everyone loses brain cells with aging, and scientists used to think that you could not make new brain cells. A study from Columbia University showed that you can make new brain cells 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). All age groups 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. 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. Anything that increases blood flow to the brain may stimulate growth of new blood vessels and brain cells, so the prevention and treatment of dementia should include exercise — the most effective way to increase growth of new blood vessels. Previous studies show that exercise increases blood flow to the brain (Sports Med, 2007;37(9):765-82), and reduces risk for diabetes and obesity which can damage the brain (Metabolism, May 2013;62(5):609-621).
Exercise helps to prolong your life and preserve your brain, but you do not have to have a specific exercise program. You just need to keep on moving. It is harmful just to sit or lie down all day long. It is healthful to mow your lawn, wash your dishes, make your bed, vacuum your house, go for a walk, and participate with your friends in activities in which you are moving your arms and legs — dancing, cycling, swimming, running, nature walks and so forth. To gain maximum health benefits from exercising and moving your skeletal muscles, you should include some sort of resistance exercise that makes muscles larger. People who have larger muscles are far less likely to suffer cognitive decline with aging than those with smaller muscles (J American Geriatrics Society, June 2023;71(5):e19-e22). If you are not already doing some type of strength-training exercise, first check with your doctor to make sure you do not have any condition that may be harmed by exercise. See Your Muscles Make Your Heart Stronger
Resistance Exercise You Can Do at Home
Dementia risk increases with age and all risk factors for dementia are the same as risk factors for heart attacks, so everyone should follow the anti-inflammatory lifestyle rules that help to prevent heart attacks, strokes, diabetes and many other diseases:
• Try to exercise every day
• Follow an anti-inflammatory, high-plant diet
• Avoid being overweight
• Avoid or severely limit alcohol
• Avoid smoking and second hand smoke
• Keep your vitamin D levels above 30 ng/mL