Thursday, February 17, 2011

Regular Walking may slow the development of Alzheimer's disease

While there is no miracle cure for the Alzheimer’s Disease, at least yet, the scientists and medical doctors performed multiple researches, validating the fact that the physical exercises have a significant positive effects on the well-being of the patients and allow to slow down the progress of disease. One of the simplest ways of performing physical activities at almost any stage of the disease and any age is walking. Even a senior with limited mobility will benefit from going on short walks.

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According to a study presented in December 2010 at the annual conference of the Radiological Society of North America Adults, people affected by Alzheimer’s disease, or mild cognitive impairment, have healthier brains when they regularly walk five to six miles a week. And the effect not only preserved brain matter in areas that handle memory and learning, but actually slowed the progression of Alzheimer's symptoms by 50 percent among participants in the study, says Cyrus Raji, MD, PhD, postdoctoral researcher in the department of radiology at the University of Pittsburgh Medical Center. “The speed of walking didn’t matter,” says Dr. Raji, who directed the study. “Slow or fast—it all had the same effect.”

For the ongoing study, Raji and colleagues analyzed the relationship between walking and brain structure in 426 people: 299 cognitively healthy adults, 83 people with mild cognitive impairment (MCI), and 44 people with Alzheimer's dementia.

When they entered the study in 1989-1990, participants were asked how many city blocks they walked in an average week, whether for exercise, chores, or any other reason. Follow-up questionnaires every three years showed that the number of blocks walked remained steady over time, Raji says.

All participants also underwent MRI exams in 1992-1994 and 1998-1999, so researchers could measure changes in brain volume.

"Brain volume is a good, reliable way" of studying brain health, Zimmerman tells WebMD. As brain cells die, brain volume drops.

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In addition, participants were given the Mini-Mental State Exam (MMSE), a brief test of cognitive skills, including attention span and memory, at various times throughout the study, with the final one five years after the second MRI scan. The MMSE is used to help doctors make a diagnosis of MCI or Alzheimer's dementia.

As shown by MRI, brain volume was preserved in healthy adults who walked at least 72 city blocks, or 6 miles, per week.

Cognitive exam and MMSE scores showed walking six miles a week was associated with a 50% decline in Alzheimer's risk over 13 years, Raji says. However, walking more than 72 blocks a week offered no additional benefit, he says.

Cognitively impaired people needed to walk at least 58 city blocks, or approximately 5 miles, per week to maintain brain volume and slow cognitive decline.

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Over 10 years, scores on the 30-point MMSE dropped by an average of five points in cognitively impaired patients who were sedentary, compared with one point in those who walked 5 miles per week.

"Going down five points is a lot," Raji says. It's the difference between being cognitively normal and cognitively impaired, he says.

The association between walking and MRI and MMSE results persisted even after the analysis was adjusted to take into account other risk factors for dementia including age, gender, and high blood pressure.

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Dr. Robert Friedland, chairman of the neurology department at the University of Louisville's School of Medicine in Kentucky, expressed little surprise at the findings, but cautioned against inferring a direct cause-and-effect link between walking and protection against cognitive decline.

"In an observational study like this, undoubtedly people who are developing cognitive disease or are likely to be in the early stages are also likely to become less active," he noted. "So, it's not possible to be sure that they're observing a direct effect of walking on the disease, because diminished walking in the group that is progressing more rapidly could have been a direct result of the disease itself."

"But that's not to say that I don't think walking is a good idea," Friedland added. "Many people have shown that physical as well as mental activity may be protective against developing disease during midlife -- that is, between [ages] 20 and 60. And I'm sure that this is also true in later life. And there are many reasons why: physical activity improves blood flow to the brain, and it changes neurotransmitters and improves cardiac function," he said. "It lessons the risk of obesity, improves insulin resistance and lowers the risk of diabetes, and lowers your blood pressure. And all of these things are risk factors for Alzheimer's disease. So, I would say that everyone at all ages should be encouraged to get as much physical exercise as they can tolerate," Friedland concluded. "Of course, we don't want people to exercise excessively if they have heart disease, for example. But with a physician's advice and supervision, walking is an excellent form of activity."

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