Being physically fit can lower the risk of dementia and delay someone developing it by nearly 18 months by boosting brain health, research has found.
Regular exercise is so helpful for maintaining cognitive function that it can even help people who are genetically more susceptible to dementia to reduce their risk by up to 35%.
The findings add to the evidence that staying fit throughout one’s life is an important way to reduce the likelihood of developing the disease.
The study, published in the British Journal of Sports Medicinefound 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 aged between 39 and 70 when they enrolled in the UK Biobank study between 2009 and 2010, none of whom had dementia at the time. They were followed for up to 12 years to see how their health progressed.
When they joined, they undertook a six-minute exercise test on a stationary bike to assess their fitness. They also measured their cognitive function through neuropsychological tests and estimated their genetic likelihood of dementia using a polygenic test to determine the risk of Alzheimer’s disease.
“Our study shows that higher CRF is associated with better cognitive function and reduced dementia risk,” the researchers write in their paper.
“Furthermore, high CRF can buffer the impact of genetic risk of all dementias by 35%.”
They add that higher CRF is associated with “lower risk of dementia and a delay in the onset of dementia over middle and older age” of 1.48 years.
The Swedish research team was led by Prof Weili Wu from the aging research center at the Karolinska Institute in Stockholm.
Dementia organizations said the findings were further evidence that people can reduce their risk by maintaining a healthy lifestyle, for example by keeping fit, not smoking and not drinking too much.
“This research highlights that exercise is an important part of maintaining a healthy lifestyle and can reduce the risk of developing dementia later in life,” said Dr Richard Oakley, the Associate Director of Research and Innovation at the Alzheimer’s association, said.
“But what’s particularly promising about this study is that exercise also reduces the risk of dementia in people who have a higher genetic risk of developing Alzheimer’s disease.”
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The Lancet medical journal’s commission on dementia which reported in July identified physical inactivity as one of 14 established factors that increase the risk of dementia. Others include hearing loss, low levels of education, air pollution, social isolation and depression.
“This new research highlights how good cardiorespiratory fitness, a key measure of overall physical health, can help lower the risk of developing dementia in the future,” said Dr Jacqui Hanley, head of research at Alzheimer’s Research UK.
“However, it is important to note that we do not know if there is a direct link between cardiorespiratory fitness and reduced dementia risk. 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 relationship between physical fitness and dementia risk.
However, they nevertheless suggest that “enhancing CRF may be a strategy for preventing dementia, even among people with a high genetic predisposition to Alzheimer’s disease”.
