People who partake in physical fitness activities are less likely to develop Alzheimer’s disease, according to a preliminary study.
Physical fitness is a state of health and well-being and is categorised as the ability to perform aspects of sports, occupations, and daily activities. Physical fitness can be achieved by a combination of a good diet, regular exercise, and other practices that promote good health.
Alzheimer’s disease is a progressive condition with symptoms developing gradually over many years. The research highlighted how regular physical fitness can lower the risk of Alzheimer’s disease prevalence.
“One exciting finding of this study is that as people’s fitness improved, their risk of Alzheimer’s disease decreased—it was not an all-or-nothing proposition,” said study author Edward Zamrini, MD, from the Washington VA Medical Center, and a member of the American Academy of Neurology. “So, people can work toward making incremental changes and improvements in their physical fitness and hopefully that will be associated with a related decrease in their risk of Alzheimer’s years later.”
The full study will be presented at the American Academy of Neurology’s 74th Annual Meeting.
Physical fitness and Alzheimer’s disease
The study involved 649,605 military veterans in the Veterans Health Administration database with an average age of 61 who were followed for an average of nine years. All participants were not diagnosed with Alzheimer’s disease at the start of the study.
The researchers set out to analyse the participants’ cardiorespiratory fitness. Cardiorespiratory fitness is a measure of how well your body transports oxygen to your muscles, and how well your muscles can absorb oxygen during exercise.
The participants were divided into five groups, which were determined by their physical fitness (least fit to most fit). Physical fitness levels were defined by how well participants did on a treadmill test. This test measures exercise capacity, which is defined as the highest amount of physical exertion a person can sustain. For individuals who are middle-aged and older, the highest level of fitness can be achieved by walking briskly most days of the week for two and a half more hours or more per week.
What the study discovered
The researchers found that the group with the lowest level of physical fitness developed Alzheimer’s at a rate of 9.5 cases per 1,000 person-years, compared to 6.4 cases per 1,000 person-years for the fittest group.
Person-years accounts for the number of people in a study as well as the amount of time spent in the study. The case rate decreased as the level of physical fitness increased, with a rate of 8.5 for the second least fit group, 7.4 for the middle group and 7.2 for the second most fit group.
Scientists adjusted for other factors that could contribute to a higher prevalence of Alzheimer’s disease. They found that individuals in the fittest group were 33% less likely to develop the disease than those in the least fit group. The second most fit group was 26% less likely to develop the disease, whilst the middle group was 20% less likely and those in the second least fit group were 13% less likely to develop the disease than those in the least fit group.
“The idea that you can reduce your risk for Alzheimer’s disease by simply increasing your activity is very promising, especially since there are no adequate treatments to prevent or stop the progression of the disease,” Zamrini concluded. “We hope to develop a simple scale that can be individualised so people can see the benefits that even incremental improvements in fitness can deliver.”
However, a limitation of this study was participants were mostly white men so the results may not be generalisable to other populations.
