February 11, 2016
To help fend off Alzheimer’s disease, it may be wise to keep walking. Walking four times a week showed benefits for the brain in older men and women with mild cognitive impairment, a type of memory loss that often precedes Alzheimer’s disease, a new study found.
The findings add to evidence that regular physical activity helps to bolster brain health and could help to fend off Alzheimer’s disease and other forms of dementia, even in those already having memory problems.
For the study, researchers at the University of Maryland School of Public Health studied 30 healthy but sedentary older adults, ages 61 through 88. Fourteen of them had mild cognitive impairment, while the remaining participants were cognitively normal.
At the start of the study, they all underwent MRI brain scans to assess the health of their brain’s cortex, a part of the brain critical for memory and thinking. Alzheimer’s disease typically results in shrinkage of the brain, including thinning of the brain’s cortex.
The study participants were then put on a 12-week exercise regimen in which they walked on a treadmill for about 30 minutes four times a week. After the exercise program, they were assessed for heart and respiratory fitness and again had their brains scanned.
Engaging in a walking exercise program improved cardiorespiratory fitness – on average, by about 8 percent. Brain scans revealed that those with mild cognitive impairment who showed the greatest improvements in cardiorespiratory fitness also showed the greatest improvements in brain cortical health.
“Exercise may help to reverse neurodegeneration and the trend of brain shrinkage that we see in those with mild cognitive impairment and Alzheimer’s,” said the study’s senior author, Dr. J. Carson Smith, an associate professor of kinesiology at the University of Maryland. “Many people think it is too late to intervene with exercise once a person shows symptoms of memory loss, but our data suggest that exercise may have a benefit in this early stage of cognitive decline.”
The findings, published in the Journal of the International Neuropsychological Society, support earlier research showing that regular moderate activity can be good for the brain, regardless of age. A 2010 study of nearly 300 city dwellers whose average age was 78, for example, found that those who walked at least 72 blocks per week — or about six miles – had less shrinkage of parts of the brain critical for thinking and memory.
Another study of 2,257 older men living in Hawaii who were in their 70s, 80s, and 90s found that those who walked the least, less than a quarter mile a day, had nearly twice the risk for Alzheimer’s and other forms of dementia compared to men who walked the most, more than two miles daily.
In another large study that surveyed more than 18,000 women aged 70 to 81, researchers found that older women who engaged in regular physical activity did better on memory and mental exams and showed less age-related memory problems than women who were less active. Women who walked at an easy pace for at least an hour and a half each week, for example, did better on memory and thinking tests than those who walked less than 40 minutes a week.
Alzheimer’s is a complex disease that likely depends on many factors, including the genes you inherit. Lifestyle factors like walking and regular exercise are likely just one part of the preventive puzzle. While a daily walk around the mall or neighborhood track won’t guarantee a physically and mentally robust old age, it may help you to look, feel and act younger.
Source: Katherine Reiter, Kristy A. Nielson, Theresa J. Smith, et al: “Improved Cardiorespiratory Fitness Is Associated with Increased Cortical Thickness in Mild Cognitive Impairment.” Journal of the International Neuropsychological Society, Vol. 21, pages 757-767, November 19, 2015.