Everyone knows fitness is important, but it can be hard to measure exactly what role it plays in health. According to one new study, exercise may be as powerful an influence on disease risk as genetic predisposition ― at least when it comes to dementia.
The study found that older adults who reported being sedentary most of the time were just as likely to develop dementia as people who are genetically predisposed to cognitive problems.
And that’s significant, considering the gene that predisposes an individual to developing dementia makes you three to four times more likely to be diagnosed with a problem like Alzheimer’s disease, Parkinson’s disease or Lewy body disease.
“The important message here is that being inactive may completely negate the protective effects of a healthy set of genes,” co-author of the study Jennifer Heisz, assistant professor in the Department of Kinesiology at McMaster University, told The Huffington Post.
And remember, the majority of individuals do not carry the genetic risk for dementia in the first place, she added.
The upside to the research is that it suggests even a little bit of regular exercise could go a long way in terms of helping prevent cognitive problems for a lot of people, Heisz said.
Walking just three times a week was linked to big benefits
For the study, 1,646 adults 65 or older had their blood analysed for the presence of the Apo-lipoprotein E allele, the gene known to be most strongly associated with dementia. No one in the study had dementia or any cognitive impairment at the start of the study.
Follow-up data collected five years after the study began showed that 331 individuals had subsequently been diagnosed with some form of dementia. The researchers also collected survey responses about whether those in the study exercised regularly.
Unsurprisingly, the data showed the odds of developing dementia over the course of the study were two times greater in individuals with the dementia allele than for those without the allele. And the data also showed that the individuals who reported not exercising regularly similarly had nearly twice the odds of developing dementia compared with the individuals without the dementia allele.
The people in the study who indicated they exercised regularly were asked two follow-up questions about their exercise habits. A majority of the study participants said walking was their primary exercise and that they did it approximately three times per week.
It’s important to point out a fairly minimal amount of exercise was found to have a big effect when it comes to dementia risk, Heisz noted. “You don’t have to train like an Olympian to get the brain health benefits of being physically active,” she said.
Experts still have questions about what type of exercise is best
This study is still epidemiological data, Heisz noted ― which means it shows a link between sedentary behaviour and dementia risk, but doesn’t necessarily explain how one leads to the other.
But taken with previous research that has linked physical activity is to lower dementia risk, the results are fairly convincing, she added. This study included a large number of individuals, it followed those individuals for five years and it controlled for other dementia risk factors, including age, heart disease, stroke, diabetes, high blood pressure, depression and smoking.
More studies are needed to identify what types of exercise provide the most benefit in terms of preventing dementia, she said ― as well as to determine the exact mechanisms in the brain that make physical activity protective when it comes to cognitive decline.
“If a physician were to ask us today what type of exercise to prescribe for a patient to reduce the risk of dementia, the honest answer is ‘we really don’t know,’” another study co-author, Barbara Fenesi, a postdoctoral fellow at McMaster, noted in a press release.
The group is conducting another study comparing different types of exercise ― including high-intensity training and moderate continuous training ― to start to answer some of those questions.
The important message here is that some physical activity does appear to be beneficial ― and being sedentary appears to increase dementia risk, Heisz said.
(The Huffington Post)