According to a recent study of physical activity as an experimental treatment for dementia, frequent, brisk walks are beneficial for people with early-stage Alzheimer’s disease because walking bolsters physical abilities and slow memory loss.
The study aimed to investigate how and why exercise helps some people with dementia, but not others. There are 1.1 million Canadians who are directly or indirectly affected by dementia. Globally, the disease affects more than 35 million people, a number that is expected to double within 20 years. There are currently no reliable treatments for the disease.
Past studies which focused on how exercise can prevent Alzheimer's disease have shown the following:
- There is a strong correlation between regular exercise and improved memories in healthy elderly people.
- Physical active older people are less likely than those who are sedentary to develop mild cognitive impairment (a common precursor to Alzheimer's disease).
- When compared to sedentary people of the same age, physically fit older people have more volume in their brain's hippocampus, the portion of the brain most intimately linked to memory function.
For the current study, researchers from the University of Kansas decided to work with people who had been given a diagnosis of Alzheimer's disease. Because the disease can affect coordination as it progresses, the study initially looked at men and women with early stage Alzheimer. Study participants had to be living at home and be able to safely walk by themselves or perform other types of light exercise.
Researchers then recruited about 70 men and women with Alzheimer's. The participants were taken to a lab at the university, where the scientists scanned their brains and tested their memories and thinking skills, aerobic endurance, and physical abilities, such as how they could rise from chairs, lift objects and so on.
All the participants were then divided into two groups. One group started a supervised walking program aimed to raise their physical fitness levels. People in this group walked progressively longer and faster over the course of several weeks, until they were briskly walking for at least 150 minutes each week. According to the researchers, in earlier experiments, the Kansas scientists had found that this routine significantly improved aerobic endurance and memory performance among older people without Alzheimer's.
The second group was the controlled group. They began stretching and toning classes designed to be light exercise that would not increase aerobic endurance but would mimic the time commitment and social interactions of the walkers.
The exercised continued for six months, at which point both groups returned to the lab for repeat testing. A few participants had left the study due to injuries. Of the ones that remain, many had improved physical functionality, scoring higher on the tests of everyday physical skills.
The effects of the experiment on thinking and memory were mixed - most people in the controlled group were slightly less able to think clearly and remember than they had been six months ago. The toning exercises did not slow the progression of dementia. Similarly, the walkers had mixed results - some scored less on the cognitive tests than the initial tests, while others were thinking and remembering much better now. Those who had improved thinking and memorization showed slight increases in the size of their brain's hippocampus.
A surprising find was that only a handful of walkers with Alzheimer's had improved endurance. In an interview with New York Times, Jill Morris, a senior scientist at the University of Kansas Alzheimer's Disease Center, who led the study, concluded: "There may be physiological differences between people with and without Alzheimer's that reach to the cellular level. In effect, the bodies as well as the brains of people with Alzheimer's disease may be unusual compared to those of healthy older people and may respond differently, if at all, to exercise. It seems likely that the right exercise programs could be disease modifying. We just don't know yet what the ideal exercise programs are."
Further research is needed. Morris and her team are currently conducting studies that will look at many different types and amounts of exercise among people with Alzheimer's. The Walk10Blocks website states that walking a minimum of about 10 city blocks each day could reduce the risk of dementia, and potentially improve cardiovascular and joint health in the long term.