Search Here

Here's another convincing reason to hit the gym: being physically fit in middle age significantly reduces the risk of developing Alzheimer's disease and other dementias later in life, a new large,  long-term study has revealed.

What's more, researchers found that the more physically fit you are in your 40s, the less likely you are to develop the neurodegenerative disease.

Researchers looked at data from nearly 20,000 healthy participants in the Cooper Center Longitudinal Study. Participants had taken a treadmill test to measure their fitness levels when they were middle-aged.  Afterwards, researchers reviewed Medicare claims data to see who was diagnosed with any type of dementia in their later years.  The study's follow-up period lasted for an average of 24 years, with participants evaluated for signs of dementia at ages 70, 75, 80 and 85.

The findings, published in the Annals of Internal Medicine, found that people who were judged to be physically in shape by the treadmill stress test in middle age were significantly less likely to develop dementia after the age of 65 compared to those who were less physically fit.

The study also found that participants who scored the highest on physical fitness tests were also the least likely to experience Alzheimer's or any other kinds of dementia after the age of 65.

The latest findings led researchers to conclude that the better shape a person is in middle age, the more protected he or she is from dementia. 

Based on the results of the study, researchers were unable to know for certain whether its exercise or fitness level that protects the brain from dementia. Study authors also noted that they could not determine how much exercise is needed for the brain to be protected from dementia. 

However, researchers say that the findings suggest that physical fitness might be a modifiable risk factor for the mind-robbing disease.

While the observational study could not prove a causal relationship between fitness and dementia, investigators say that a cause-and-effect relationship is possible.  For instance, greater physical fitness reduces a person's risk for other known risk factors of dementia such as diabetes and hypertension.  In addition, past studies have also linked physical fitness to brain volume, neural plasticity, neurotrophic factors, and beta-amyloid protein deposits, according to Medpage Today.

"Future studies should address the dose-response relationship with physical activity needed to modify fitness levels to inform public health recommendations for dementia prevention," researcher Dr. Laura DeFina of the Cooper Institute in Dallas and her team wrote in the study.

"In addition, studies on the effect of midlife physical activity and fitness levels on brain structure and function may further elucidate the mechanism(s) of the protective effect of fitness levels."

In an accompanying editorial, dementia expert Mary Sano, of Mount Sinai School of Medicine in New York City wrote that based on the latest findings, exercise "seems to be a reasonable prescription for dementia prevention."

While researchers do not know for sure how physical fitness may preserve brain function, they say that keeping the heart healthy is essential to keeping the brain healthy.  However, they note that it's important for people, especially those with any health conditions, to talk to their doctor before beginning a new exercise regimen.

Dr. Richard Isaacson, director of the Alzheimer's division at the University of Miami Miller School of Medicine, told HealthDay that recent studies show that brain changes that lead to dementia often occur two to three decades before the onset of symptoms.

"If you are worried about developing Alzheimer's or dementia, the time to make healthy lifestyle choices and changes is now," Isaacson said, according to HealthDay.

Isaacson explains that a healthy lifestyle is one that consists of regular exercise and a healthy and low-fat diet.  People also need to make sure that they have healthy blood pressure and cholesterol levels.

"There is no magic bullet that will prevent Alzheimer's, but we have evidence that you can reduce your risk," Isaacson said. "This is an excellent study because it uses an objective measure of fitness: the treadmill test."

Study authors say that aiming for the government recommended 150 minutes of moderate exercise or 75 minutes of vigorous exercise per week could help improve long-term health.

"The needle has not been pushed far enough on physical activity," DeFina said, according to HealthDay. "We are not a moving nation at this point, and this is another bit of evidence to encourage people to exercise."