The Veterans Health Administration database contained 649,605 service veterans with an average age of 61 who were monitored for an average of nine years. They didn't have Alzheimer's disease when the trial began.
The cardio-respiratory fitness of the subjects was measured by the researchers. The ability of your body to deliver oxygen to your muscles and the ability of your muscles to absorb oxygen during exercise is measured by cardio respiratory fitness.
Alzheimer’s disease was diagnosed at a rate of 9.5 cases per 1,000 person-years in the group with the lowest fitness level, compared to 6.4 cases per 1,000 person-years in the healthiest group. With 8.5 for the second least fit group, 7.4 for the middle group, and 7.2 for the second most fit group, the case rate declined as fitness level climbed.
When additional characteristics that could influence the risk of Alzheimer’s disease were taken into account, researchers discovered that those in the fittest group were 33 percent less likely to get the condition than those in the least fit group.
The second most fit group had a 26% lower risk of developing the disease, the middle group had a 20% lower risk, and the second least fit group had a 13% lower risk than the least fit group.
The National Institute on Aging, the National Institutes of Health, the United States Department of Veterans Affairs, the Washington D.C. VA Medical Center, and George Washington University all contributed to the research.
Parvathy Sukumaran 
