December 4, 2024
People who have a genetic predisposition to Alzheimer’s disease may lower their risk of developing the illness with a workout routine, according to a new report. The study found that men and women with high levels of cardiorespiratory fitness in middle age and beyond were 35 percent less likely to develop Alzheimer’s disease or other forms of dementia in old age compared to their less fit peers. The benefits of exercise were particularly pronounced in those at increased genetic risk of Alzheimer’s because they carried the APOE-E4 gene variant or other genetic factors that predispose to the disease.
“Enhancing cardiorespiratory fitness could be a strategy for the prevention of dementia, even among people with a high genetic predisposition for Alzheimer’s disease,” the authors stated. The findings were published in the British Journal of Sports Medicine.
For the study, researchers from the Karolinska Institute in Stockholm and other medical centers analyzed health records from 61,214 men and women who were part of the UK Biobank, a database containing in-depth genetic and medical information from half a million British citizens over many years. They ranged in age 39 to 70 at the start of the study period, from 2006 to 2010.
At the beginning of the study period, participants underwent a six-minute fitness test on a stationary bicycle to assess their cardiorespiratory fitness, a measure of the ability of the heart, blood and lungs to supply oxygen to muscles during physical exertion. They were grouped into low, medium or high levels of cardiorespiratory fitness, standardized according to their age and sex.
Researchers assessed individuals’ genetic risk for Alzheimer’s disease, according to standard research-based DNA analyses of genes linked to the disease. Participants also underwent tests of memory and thinking skills to assess their cognitive health. All were free of Alzheimer’s disease or other forms of dementia when the study began.
Participants were followed for about 12 years, including with follow-up cognitive tests. During that time, 553 of them developed Alzheimer’s disease or another form of dementia.
The researchers found that overall, the more aerobically fit someone was in middle age, the better their cognitive health was more than a decade later. Cardiorespiratory fitness seemed to benefit multiple facets of memory, such as recalling specific words, names and numbers or remembering specific tasks, such as making an appointment.
The greatest benefits were observed in individuals with a genetic predisposition for Alzheimer’s. Those with the highest levels of cardiorespiratory fitness had a 35 percent lower relative risk of developing the disease compared to their least fit peers. Aerobic fitness delayed the onset of dementia by the equivalent of about one-and-a-half years, the researchers found.
“Our study shows that higher cardiorespiratory fitness is associated with better cognitive function and decreased dementia risk,” the authors concluded. “Moreover, high cardiorespiratory fitness may buffer the impact of genetic risk of all dementia by 35 percent”
The study was observational and cannot prove cause and effect. But it involved a large study population, and earlier research has shown that greater cardiorespiratory fitness is linked to a lower risk of serious diseases such as heart disease, stroke or cancer and a lower risk of dying young.
Cardiorespiratory fitness declines by around 3 percent to 6 percent per decade when we are in our 20s and 30s, but the decline accelerates to more than 20 percent per decade by the time we reach our70s.
Experts say the best way to help minimize cardiorespiratory decline as we age is by choosing an activity you enjoy, such as walking, running, biking or a dance or spin class, and to do it regularly for at least half an hour several days a week. Aim to perform the activity at a fairly rigorous level, in which it would be difficult to hold a conversation with a friend. You can also mix it up, aiming for brief periods of high-intensity exercise amid longer periods of lower intensity exertion.
If you’re just getting started, see your doctor to make sure the exercise plan is right for you. And don’t forget other lifestyle factors that can promote brain health, including a heart-healthy diet and a good night’s sleep.
By ALZinfo.org, The Alzheimer’s Information Site. Reviewed by Eric Schmidt, Ph.D. Fisher Center for Alzheimer’s Research Foundation at The Rockefeller University.
Source: Shuqi Wang, Liuao Xu, Wenzhe Yang, et al: “Association of cardiorespiratory fitness with dementia risk across different levels of genetic predisposition: a large community-based longitudinal study” British Journal of Sports Medicine, November 19, 2024
