London - Taking 20 minutes of exercise three times a week could drastically reduce the risk of Alzheimer’s, research shows.
Cambridge scientists say that even getting off the bus one stop early and walking the rest of the way could help prevent the devastating illness.
They have found that a third of all cases are due to lifestyle reasons including inactivity, obesity, smoking, high blood pressure and having a poor education. But of these, a lack of exercise was found to be the single most important cause.
Researchers believe regular physical activity ensures there is a steady flow of oxygen-rich blood to the brain. This is thought to prevent the build-up of plaques, deposits of protein in the brain which cause Alzheimer’s.
AFP reports that Alzheimer's is an age-related brain condition that experts suspect is influenced by both genes and the environment.
The population boom and longer lifespans mean that more than 106 million people will be living with Alzheimer's by 2050 compared with 30 million in 2010, according to predictions.
The study, led by Carol Brayne, a professor of public health at at the University of Cambridge, looked at seven risk factors for which there was strong evidence of an association with the disease.
These were diabetes, midlife hypertension, midlife obesity, physical inactivity, depression, smoking and low educational attainment.
By reducing the relative risk from each of these factors by 10 percent, it should be possible to slash global prevalence of Alzheimer's in 2050 by 8.5 percent, preventing nine million cases, it said.
Professor Brayne said: “The important message is that there are aspects of healthy life which reduce risk.
“This doesn’t say we can prevent dementia and Alzheimer’s altogether. But there is a proportion which is preventable. Even just having a vigorous walk a few times a week, and ideally make it social event. It’s really difficult for many people to take exercise. If nothing else is possible, even a walk will help. That’s what evidence suggests.
“So 20 minutes to half an hour, three times a week. I would say to just fit something into life in the best possible way. This might be getting off the bus stop the next stop up, and walk the last bit.’
Professor Brayne said that if someone started exercising they would be more inclined to eat healthily and give up smoking, further reducing their risk of dementia.
The research, published in the journal Lancet Neurology, looked at almost 30 studies linking dementia to various lifestyle causes. A lack of exercise contributed to 22 percent of cases, twice as many as any other cause.
Other researchers are trying to establish exactly how physical activity prevents dementia and if any particular type is more effective. They suspect that it keeps the heart and blood vessels strong, which maintains a steady flow of blood to the brain. This may prevent the build-up of plaques, protein deposits in the brain which are thought to trigger Alzheimer’s
But Professor Brayne said that in the meantime, adults should try to fit exercise into their lives. “Simply tackling physical inactivity, for example, will reduce levels of obesity, hypertension and diabetes, and prevent some people from developing dementia, as well as lead to a healthier old age in general - it’s a win-win situation.’
Dr Doug Brown, of the Alzheimer’s Society, said: “This valuable study adds to a growing body of evidence strongly suggesting that simple lifestyle changes can help lower our risk of developing dementia. Regular exercise is a good place to start, as well as avoiding smoking and eating a Mediterranean diet.”
Statistically, one in three adults over 65 will develop dementia. Alzheimer’s is the most common form. - Daily Mail