March 8, 2013 at 10:10 AM ET
The statistics are not comforting: One in eight adults aged 65 and older suffers from Alzheimer's disease. But a new study in the Annals of Internal Medicine offers the heartening news that being fit in middle age may help stave off dementia later in life.
The researchers are among the first to use a large sample size to examine the relationship between cardiovascular fitness and loss of brain function. They analyzed data from The Cooper Center Longitudinal Study, a database of patient visits to the Cooper Clinic in Dallas, Texas, which has been previously used to link greater fitness to longer life-expectancy and a lower risk of stroke, diabetes and other diseases.
Researchers in the new study compared the midlife fitness levels of 19,458 generally healthy people to the number of those people who were diagnosed 19 to 30 years later with dementia. Fitness levels were measured by a treadmill test. Compared to the least fit people, those with the highest level of conditioning had a 36 percent lower risk of developing any form of dementia.
The study used age- and gender-graded fitness levels and defined "low fit" as the bottom 20 percent of study participants and the highest fitness levels as the top 20 percent. Those fitness levels roughly corresponded to someone who could jog slowly versus an endurance runner.
The study is unique in that it examined fitness levels rather than relying on self-reported activity. But because it didn't control for other lifestyle activities like healthy eating habits, it cannot conclude that cardiovascular fitness was the direct cause of lower Alzheimer risk. But it provides more evidence that exercise pays off in the long run.
"We've known that exercise is beneficial to brain health in the short-term," Laura DeFina, MD, the study's lead author, told Runner's World Newswire. "This study proves that we can do something today to affect not only our physical health, but also our brain health for the future."
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