1 of 2 | Even those who exercise once or twice a week can help ward off dementia, a new study concludes. Photo by Andrea Piacquadio/
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NEW YORK, Oct. 29 (UPI) -- Being a "weekend warrior" -- engaging in exercise once or twice per week -- may be as beneficial as regular sessions in decreasing the risk of cognitive decline that often leads to dementia, a new study concludes.
The study was published Tuesday online in the British Journal of Sports Medicine.
Researchers noted this strategy could be an easier way for people with hectic schedules to stay fit. They also said that it's vital to identify potentially modifiable risk factors for dementia early because delaying its onset by five years could reduce the prevalence in half.
"My colleagues and I have conducted large studies in Mexico and the United Kingdom that suggest that being a 'weekend warrior' reduces the risk of death," the study's lead investigator, Gary O'Donovan, told UPI.
"We undertook this study because we wanted to investigate whether being a weekend warrior also offers mental health benefits," said O'Donovan, an adjunct professor at Universidad de los Andes in Bogotá, Colombia.
He said this research "is more good news for busy people around the world. Lack of time is a major barrier to physical activity."
As far as the researchers know, it's the first study of this type to reveal that exercise patterns of weekend warriors and regularly active individuals correlated with similar declines in mild dementia risk.
They relied on survey data from the Mexico City Prospective Study to analyze responses from 10,033 people averaging 51 years old at the start of the work.
A total of 7,945 respondents said they didn't exercise at all; 726 met the weekend warrior definition; 1,362 reported exercising several times per week; and 2,088 made up a combined group.
During an average 16-year monitoring period, researchers identified 2,400 cases of mild dementia. The prevalence was 26% among the no exercisers, 14% among the weekend warriors and 18.5% among the regularly active.
After considering other potential variables such as age, educational attainment, smoking, nightly sleep, diet and alcohol intake, researchers calculated the risks of developing mild dementia for each group.
When compared with the no exercisers, the risks were 25% lower for weekend warriors and 11% lower for the regularly active. The risks were 16% lower in the combined group.
If all middle-aged adults exercised at least once or twice a week, it may be theoretically possible to avoid 13% of mild dementia cases, researchers estimated.
The researchers suspected that the seemingly protective effect of exercise on brain health may stem from increased brain-derived neurotrophic factor concentrations -- molecules that support the growth and survival of neurons -- and brain plasticity.
They also noted a connection between exercise and greater amounts of brain volume, executive function and memory.
Other experts commended the researchers on their illuminating findings.
"Every time you exercise and increase your blood flow, even if you're a weekend warrior, it's triggering the removal of amyloid in the brain, which is what causes Alzheimer's [disease]," said Dr. Rudy Tanzi, director of the Genetics and Aging Research Unit at Massachusetts General Hospital in Boston.
Tanzi, who was not involved in the study, described amyloid as "a sticky, toxic material that accumulates outside of nerve cells, beginning decades before symptoms of Alzheimer's."
Exercise also stimulates "the birth of new nerve cells in the brain, especially in the region that is most vulnerable in Alzheimer's disease -- the hippocampus," he said.
Brittney Lange-Maia, an epidemiologist and assistant professor at Rush Alzheimer's Disease Center in Chicago, said "there is currently no cure for dementia, so identifying factors related to lower risk and developing strategies to prevent the disease are crucial."
She said "this study adds to the growing body of literature showing that midlife lifestyle is important for late life health, and the 'dose' of physical activity that was associated with lower dementia risk may be feasible for many people to consider adding to their lifestyle."
Dr. John Absher, a neurologist at Prisma Health in Greenville, S.C., said he would encourage people to commit to an enjoyable sport or other form of exercise at least once or twice per week.
"If you do this consistently, you may feel more motivated to pursue a pattern of more frequent and regular physical activity" and reap the benefits of improved brain health, Absher said.