Dr. Aron Buchman, lead author of the study, declared:
The implications ... are really astounding. Exercise is good, without a doubt, but this study is about more than just exercise. Older people who might not be able to exercise can tailor activities that are right for them. This is an important message for society as the largest growing segment of our population is old people. We need to be encouraging physical activities even in very old individuals, even if their health doesn't allow them to take part in fitness programs.
These activities include housework, gardening, and even playing cards. It has been known for a number of years that nuns, who have a regimen of daily activities that include prayers, reading and meditation even among older nuns, have a significantly lower rate of Alzheimer’s than the general population. Last year the Aging Project found that higher levels of social activity also reduce the risk of dementia.
The newly-released study looked at 716 people over the age of 70 and found that 71 of them began to develop symptoms of Alzheimer’s during the project. Participants wore an “actigraph” on their wrists in addition to reporting what they did during the day. The average amount of their physical activity per week was 3.3 hours. Those in the bottom 10 percent in terms of intensity of activity were found to be much more likely to develop Alzheimer’s — indicating the importance of not just activity itself, but also its intensity. Those conducting the study did not attempt to identify which types of activities were most beneficial.
Doctor Gary Kennedy, Director of Geriatric Psychiatry at Montefiore Medical Center in New York, noted of the findings: "We’ve known that muscle activity generates neurons in the brain, but this study gives us additional motivation. It shows that you don’t have to go to the gym. Older people very often don’t want to do that."
The results did not vary according to either age, sex, education, body mass, mood, or vascular conditions. Additionally, the gene APOE4, which is associated with a higher risk of developing Alzheimer’s, did not change the findings.
Rush University's new study dovetails with other recent similar research. At the 2010 annual meeting of the Radiological Society of America, Dr. Cyrus Raji of the University of Pittsburgh observed,
In cognitively normal adults, walking six miles a week instead of being sedentary was associated with a 50% reduction in Alzheimer’s risk over 13 years. For people with MCI [mild cognitive impairment], walking just five miles a week reduced brain atrophy and cognitive decline by more that 50%.
Raji added that the evidence indicated that increasing the amount of physical exercise over 5-6 miles a week did not appear to provide a commensurate reduction in the risk of Alzheimer’s.
Dr. Robert Zimmerman, a neuroradiologist at New York-Presbyterian Hospital who moderated the presentation, reported that participants were given MRI exams at intervals of several years to determine brain volume: Brain volume," he explained, "is a good, reliable way” to determine brain health. Participants in this study were also given mental assessment tests to determine the rate of decline in cognitive functions, the results of which supported the MRI findings linking a moderate amounts of regular walking to a diminution of
the risk of developing Alzheimer’s. Interestingly, the benefits of walking were not affected by blood pressure, age, or similar factors.
Much of what medical research is discovering today would have fallen under the category of simple common sense in past generations. Keeping busy, getting fresh air and sunshine, exercising regularly in moderate activities such as walking — these are the sorts of things people have long known were important to health. And now the numbers show they're important to mental health as well.