As people age, the risk of developing Alzheimer’s disease or another dementia increases. Perhaps you have seen Alzheimer’s in your own family and wonder if you’re at risk. Or maybe you’ve watched dementia affect the life of your friend. You may simply be aware of the high number of people who develop Alzheimer’s and be concerned about how to avoid it. Currently, approximately 5.4 million people in the United States have Alzheimer’s. The question for many is: Can Alzheimer’s be prevented?
What Causes Alzheimer’s?
In order to prevent or reduce the risk of Alzheimer's, it's helpful to know what causes it. However, scientists are still working on determining exactly what triggers Alzheimer’s. What we do know is that the brain begins to produce extra beta-amyloid and tau proteins. Those proteins then start to tangle and build up in and between brain cells. Eventually, connections between brain cells are lost and brain tissue actually deteriorates in function and size. It appears that these physical changes in the brain begin many years before any signs of impaired memory or other cognitive concerns appear.
What we don’t know for certain is what causes those changes to begin. Genetics appears to cause a predisposition for some people, giving them a higher chance (but not a certainty) of developing Alzheimer's. Additionally, advanced age plays a role. But other controllable factors, including physical health, have been associated with decreasing the risk of developing Alzheimer’s.
Since we can't yet determine with certainty exactly what triggers Alzheimer's, the next best thing is to rely on research that demonstrates an association between factors. For example, research has shown that both the risk of developing Alzheimer's and a delay in the onset of symptoms, have been connected with factors that include diet, mental exercise, social interaction, physical exercise and more. In light of that, here's a closer look at physical exercise.
Exercise as Prevention
Several studies have demonstrated correlations between a decreased chance of developing Alzheimer's (or other types of dementia) and physical exercise. These studies include ones where self-reports of physical activity in early to midlife were associated with better brain health later in life, structured exercise classes were correlated with a change in the size of areas in the brain such as the hippocampus, and different types of exercise were compared to see which was most effective for maintaining or improving brain health.
Additionally, if our cholesterol is in a healthy range, we’re less at risk for events like a stroke that could trigger vascular dementia. Exercise gets the blood flowing through our bodies and brains. Being physically healthy doesn’t eliminate the possibility of Alzheimer’s or another dementia developing, but a healthy body does decrease the risk.
According to the Alzheimer’s Association, “Some of the strongest current evidence links brain health to heart health. Your brain is nourished by one of your body's richest networks of blood vessels. Every heartbeat pumps about 20 to 25 percent of your blood to your head, where brain cells use at least 20 percent of the food and oxygen your blood carries.”
What Kind of Exercise Is Best?
You may be wondering what type of exercise you should participate in to reap the benefit of a lower risk of Alzheimer’s. The answer depends on whom you ask. One study concluded that resistance training/weight lifting was the most effective at maintaining and even improving cognitive functioning. Other research has studied walking/aerobic exercise with good results. Some studies have shown a benefit from simply a higher level of general physical activity.
While researchers might debate the answer to this question, the general consensus is that exercise, whatever kind you choose, is beneficial to your body and your brain. Consider this your encouragement to invest in your health, and don’t forget to consult with your physician before starting a new exercise program, especially if you have other health concerns.
Alzheimer’s Association. Prevention. Accessed July 19, 2012. http://www.alz.org/research/science/alzheimers_prevention_and_risk.asp#exercise
Alzheimer's Association. The Search for Causes. Accessed July 19, 2012. http://www.alz.org/research/science/alzheimers_disease_causes.asp
Alzheimer's Association. What Is Alzheimer's? Accessed July 19, 2012. http://www.alz.org/research/science/alzheimers_research.asp
Brain, Behavior and Immunity. Voluntary exercise protects hippocampal neurons from trimethyltin injury: Possible role of interleukin-6 to modulate tumor necrosis factor receptor-mediated neurotoxicity. Accessed July 19, 2012. http://www.sciencedirect.com/science/article/pii/S0889159111000808
Fisher Center for Alzheimer’s Research Foundation. Fitness and Good Mental Health: Exercise Brings Many Benefits. Accessed July 19, 2012. http://www.alzinfo.org/11/alz-guide/fitness-good-mental-health-exercise-brings-benefits
Neurology. Preventing Alzheimer with Exercise? April 24, 2012 vol. 78 no. 17. Accessed July 17, 2012. http://www.neurology.org/content/78/17/e110.full