Regular physical activity may help ward off dementia years later

Older adults who engage in vigorous physical activity three or more times a week are less likely to be diagnosed with dementia later  compared to adults who don’t, according to a new longitudinal study in American Journal of Health Promotion.

“The key finding is that physical activity may be a preventative strategy for dementia, and it is a relatively easy behavioral modification we can all do,” said the study’s lead author Mary Elizabeth Bowen, Ph.D., research health science specialist at James A. Haley Veterans Hospital in Florida. “There is also evidence that physical activity has cognitive benefits even if a person has other health concerns.”

Researchers examined the effects of self-reported physical activity at age 71 from 808 adults in two ongoing national studies of aging. On three separate occasions, participants were asked whether they engaged in vigorous physical activity such as biking, running, involvement in sports and heavy household work, over the past year.  

Bowen and her colleagues found that people who reported vigorous physical activity three or more times per week were 25 percent less likely to be diagnosed with dementia three to seven years later. There was no difference between the groups for other health conditions such as high blood pressure or diabetes.

Bowen noted, “It is interesting that the affects of physical activity on dementia remained robust despite considerations of other factors such as genetics, health behaviors and health conditions in this older adult population.”

Barbara B. Bendlin, Ph.D., assistant professor at the University of Wisconsin School of Medicine and Public Health, wasn’t surprised by the study’s conclusions. “These are interesting findings and add support to other studies showing that exercise may be beneficial in reducing the risk for Alzheimer’s disease and other dementia.”

Considering the study’s self-reporting measures Bendlin said, “Possibly using other measures like a motion sensor, or measuring a person’s oxygen consumption during exercise could provide a more objective measure.  Another potential conundrum is that we can’t know from this type of study whether people who are more physically active are at reduced risk for developing dementia, or whether developing dementia causes people to exercise less. Behavioral changes associated with dementia can manifest several years before the disease is diagnosed, so it may be that reduced activity levels are actually a symptom of the dementia process.”