Being physically fit can lower the risk of dementia and delay its development by almost 18 months by improving brain health, research shows.
Regular exercise is so helpful in maintaining cognitive function that it can even help people with a genetic predisposition to dementia reduce their risk by up to 35%.
The findings add to evidence that staying fit throughout life is an important way to reduce the risk of developing the disease.
The study, published in the British Journal of Sports MedicineResearch found that people with the highest cardiorespiratory fitness (CRF) also had higher cognitive function and a lower risk of dementia.
The researchers analyzed the health of 61,214 people who were aged between 39 and 70 when they enrolled in the UK Biobank study between 2009 and 2010. None of them had dementia at the time. They were followed for twelve years to see how their health progressed.
When they joined, they underwent a six-minute exercise test on an exercise bike to assess their fitness. They also had their cognitive function measured using neuropsychological tests and their genetic likelihood of dementia was estimated using a polygenic test to assess the risk of Alzheimer’s disease.
“Our study shows that a higher CRF is associated with better cognitive function and a reduced risk of dementia,” the researchers write in their paper.
“In addition, a high CRF can buffer the impact of genetic risk on all forms of dementia by 35%.”
They add that a higher CRF is associated with “a lower risk of dementia and a delay in the onset of dementia in middle and older age” of 1.48 years.
The Swedish research team was led by Prof. Weili Wu from the aging research center of the Karolinska Institute in Stockholm.
Dementia organizations said the findings are further evidence that people can reduce their risk by maintaining a healthy lifestyle, for example by keeping fit, not smoking and not drinking excessively.
“This research highlights that exercise is an important part of maintaining a healthy lifestyle and could reduce the risk of developing dementia later in life,” said Dr Richard Oakley, deputy director of research and innovation at the Alzheimer’s Society.
“But what is particularly promising about this study is that exercise also appears to reduce the risk of dementia in people with a higher genetic risk of developing Alzheimer’s disease.”
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The committee on dementia of the medical journal The Lancet says so reported in July identified physical inactivity as one of 14 established factors that increase the risk of dementia. Others include hearing loss, low education levels, air pollution, social isolation and depression.
“This new research highlights how good cardiorespiratory fitness, an important measure of overall physical health, could help reduce the risk of developing dementia in the future,” said Dr Jacqui Hanley, head of research at Alzheimer’s Research UK.
“It is important to note, however, that we do not know whether there is a direct link between cardiorespiratory fitness and a reduced risk of dementia. More research is needed to find out exactly how it affects the brain.”
The researchers themselves emphasized that their findings were observational and did not necessarily prove a causal link between physical fitness and the risk of dementia.
Nevertheless, they suggest that “improving CRF could be a strategy for dementia prevention, even in people with a high genetic predisposition to Alzheimer’s disease.”