By Karen Kaplan, Los Angeles Times/For the Booster Shots blog
Even if you’re 80 or older, it’s not too late for daily exercise to reduce your risk of developing Alzheimer’s disease, according to a new study. And if hitting the gym isn’t quite your style, here’s more good news: You can also benefit by doing housework, researchers say.
Plenty of research has suggested that people who make a habit of exercising are less likely to get Alzheimer’s, though scientists aren’t sure how to explain the link. Other activities that have been correlated with a reduced risk for Alzheimer’s include engaging one’s brain in mentally stimulating activities, spending time in social groups and eating a healthful diet, according to the National Institute on Aging.
The new study, published in the journal Neurology, involved 716 people who were part of the Memory and Aging Project at Rush University Medical Center in Chicago. All of the volunteers wore a device called an actigraph on their wrist 24 hours a day for about nine days to record their level of physical activity (including chores like cooking, cleaning and washing dishes). The average age of the volunteers was 81, and about three-quarters of them were women. They were tracked for 3.5 years, on average.
Over that time, 71 of the volunteers developed Alzheimer’s. Comparing them with the others who remained Alzheimer’s-free, the researchers found that the 10% who got the least amount of exercise were 2.3 times more likely to get the disease compared with the 10% who got the most exercise. (This calculation took into account the age, sex and education of the volunteers.) Those who spent the least time engaging in intense physical activity also had a higher risk.
||The researchers went on to see if other factors -- such as body mass index, chronic health conditions, and even a gene variant known to increase one’s risk for developing Alzheimer’s -- affected the result. In all cases, they reported that the link between exercise and Alzheimer's remained statistically significant.
The findings could have serious implications for public health, considering that the number of senior citizens in the U.S. is forecast to reach 80 million by 2030, the researchers wrote. Among these elders, the fastest-growing group will be people who are 80 or older.
In an editorial that accompanied the study, Michal Schnaider Beeri of the Mount Sinai School of Medicine in New York and Laura Middleton of the University of Waterloo in Canada said that octogenarians should take heed.
“These results may have substantial pragmatic implications for public health: Motivating the elderly to be physically active, even if mobility is limited, may decrease their risk of developing AD,” they wrote. “In a world that is becoming progressively sedentary, and in the context of very limited success of the currently available medications to treat or delay AD, physical activity provides a promising, low-cost, easily accessible, and side-effect–free means to prevent AD. In addition, physical activity has other beneficial effects on quality of life, combating cardiovascular disease, risk of falls, disability, and depression.”