-Alzheimer disease is a global degenerative disease of the brain. As we age, there is an important link between physical activity and brain health. There is an increasing amount of evidence pointing to the importance of muscle weakness and the development of Alzheimer disease.

In the November issue of the journal Archives of Neurology, researchers report that the loss of muscle strength is associated with the development of Alzheimer disease and mild cognitive impairment (age-related minor difficulties in memory and concentration.)

Investigators studied more than 900 elderly people without dementia at baseline.
During the follow-up period of more than three years, a total of 138 people developed Alzheimer’s disease.
Increased muscle strength at the beginning of the study was associated with a 43% lower risk of developing Alzheimer disease during the study period.
Additionally, increased muscle strength was also associated with a 33% slower rate in the decline of normal concentration and memory.

Alzheimer disease has previously been thought of as degenerative process of higher brain functions such as memory, problem solving and concentration. In this study the investigators showed this impairment also affects the motor areas of the brain, the part of the brain used to control muscle movement.

This study is important for two reasons. First, it shows us that muscle strength was associated with a substantially decreased risk of Alzheimer disease and mild cognitive impairment, suggesting that impaired muscle strength precedes the development of cognitive impairment in aging.
Second, the study indicates that there are possible benefits between exercising and maintaining brain health and possibly staving off the development of Alzheimer disease.

Cristopher Geiler, MD

Arch Neurol. 2009;66(11):1339-1344