To date, scientists have not discovered how to prevent or cure Alzheimer’s disease, a form of dementia that affects more than 5 million people in the United States and is the sixth leading cause of death. However, recent research shows that exercise may help preserve cognitive function in those at risk for developing the disease, and could be a useful alternative or adjunct to drug therapy in slowing the disease’s progression in those affected.
What is Alzheimer’s Disease?
Alzheimer’s disease is a form of dementia that causes a progressive decline in mental ability and affects an individual’s capacity to perform daily tasks. It is usually accompanied by memory loss, altered thought patterns, and behavioral changes. The disease is not considered to be a part of normal aging, although it predominantly affects those who are 65 or older. A small percentage of individuals (approximately 5 percent) experience early onset of the disease in their 40s or 50s.
What are the Signs and Symptoms of Alzheimer’s Disease?
Common signs of Alzheimer’s are listed below. In the early stages of the disease, mild memory loss is common, but eventually, affected individuals may withdraw, becoming unresponsive to their environment, disoriented, and unable or unwilling to interact with the people in their lives. In advanced stages, they may even have difficulty speaking, walking, or swallowing.
Common Signs and Symptoms of Alzheimer’s Disease
- Memory loss, especially the inability to recall recently learned information
- Difficulty concentrating or solving problems
- Trouble completing familiar tasks
- Mood swings and personality changes
- Confusion about time, place, or events and unfounded suspicions about family members, friends, or caregivers
- Trouble recalling words and following or participating in conversations
- Trouble interpreting visual or spatial cues
- Altered judgment, which sometimes leads to risky behaviors
- Withdrawal from previously pleasurable activities or social situations
- Misplacing objects and difficulty performing activities with sequential steps
How Exercise Benefits Cognition
Exercise has long been known to have positive health effects at all ages and stages of life. For instance, it helps decrease stress, reduce the risk of diabetes and cardiovascular disease, and improve bone and muscle strength. But did you know that research has also shown that exercise can benefit those at risk for or diagnosed with Alzheimer’s disease? Indeed, exercising for a half hour to an hour several times a week may:
- Delay the onset of Alzheimer’s for people at risk for developing the disease
- Improve overall cognitive function (e.g., thinking, reasoning, memory, and judgment) in individuals with mild Alzheimer’s disease or mild cognitive impairment (MCI)
- Slow the progress of Alzheimer’s disease in people who are diagnosed with the condition
- Reduce the risk of falls
Below are just some of the findings from recent studies that examine the benefits of exercise for individuals with cognitive impairment associated with Alzheimer’s disease.
- A study conducted by researchers from the University of Maryland School of Public Health and published in the Journal of Alzheimer’s Disease revealed that 150 minutes of exercise per week improved cognitive function in people with MCI – the type of early memory loss associated with Alzheimer’s disease. It was the first study to show that a moderate-intensity exercise program for older adults with MCI (average age of 78) improved not only memory recall, but also brain function, as measured by functional magnetic resonance imaging (fMRI). The areas of the brain that showed improved efficiency were the same areas that are affected by Alzheimer’s – specifically those areas known to control episodic memory and memory encoding/retrieval.
- Another study by scientists at the Cleveland Clinic in Ohio corroborated the beneficial effects of exercise on the brain. The results, published in 2014 in Frontiers in Aging Neuroscience, indicated that even moderate exercise may help slow the progression of Alzheimer’s disease by limiting shrinkage of the hippocampus, a portion of the brain involved in memory processing. Basically, the study revealed that the brains of physically active participants who were known to carry the e4 gene, a marker for a substantially increased risk of the disease, looked much like the brains of subjects who had a much lower risk for the disease. By contrast, the brains of non-active subjects at high risk for Alzheimer’s disease showed significant atrophy of the hippocampus during the same time period.
Animal research also shows the positive effects of exercise on cognitive function. In one study, scientists tested learning in two groups of caged mice. One group had access to an exercise wheel and one did not. The animals that exercised performed better and faster on a Morris water maze test than the non-active mice. The results also indicated that levels of brain-derived neurotropic factor (BDNF), which is known to stimulate neurons, increased in the animals that exercised, particularly in the areas of the brain that control thinking and learning.
Additional studies are necessary to determine how exercise affects cognitive function, as well as the potential role of physical activity in improving memory and learning and slowing the progression of cognitive and functional decline in individuals with Alzheimer’s disease. What is clear is that the research conducted thus far indicates that even moderate exercise may benefit cognition, and it certainly improves overall health and fitness for people of all ages.