Stronger Muscles May Reduce Alzheimer's Risk
Research published in the November Archives of Neurology has found that older adults with strong muscles have a 61% lower chance of developing Alzheimer’s disease. The stronger participants also showed a slower overall decline in mental abilities, a precursor to Alzheimer’s.
Researchers at the Rush University Medical Center in Chicago, led by Dr. Patricia Boyle, studied 970 retired adults over a 4-year period with an average age of 80 who did not initially have Alzheimer’s or other mental impairment. Each was given a score of mental function and physical strength, testing 11 muscle groups. Scores ranged from negative 1.6 to positive 3.3. Every unit increase in muscle strength correlated with a 43% reduction in the risk of developing Alzheimer’s.
Alzheimer's disease, the most common form of dementia, causes a progressive loss of memory and thinking ability. It is also associated with other symptoms such as an impaired gait, depression and a weakened grip. It currently affects about 35 million people worldwide.
Scientists are uncertain about the reason for the link. One theory proposed that there is a common cause for the loss of muscle and failing mental abilities, such as damage to the cell mitochondria that generate energy in the body. The overall decline in energy production may cause decreasing muscle strength initially and then cognitive decline.
Another possibility is a health condition that causes reduced strength, such as a stroke or nervous system disorder, can expose previously hidden symptoms of Alzheimer’s disease. As per Dr. Susanne Sorensen, head of research at the Alzheimer’s Society, “'In Alzheimer’s disease, changes in the brain begin many years before a person begins to develop symptoms of dementia.”
A third theory is that physical active adults may maintain their mental abilities more so than those not active. Other studies have linked grip strength to Alzheimer's, while a person's weight and level of physical activity also influence risk of the disease. A June study by the Association for Psychological Science found that exercise helps people with executive functioning, short-term memory, and maintaining focus and attention.
"We certainly think that it is important to be physically active and to work to keep our muscles strong," said Dr. Boyle. "Good physical health is important for good brain function."