2006年VOA标准英语-Exercise May Reduce Chance of Developing D（在线收听）

By Carol Pearson
Washington, DC
19 January 2006
 
watch Dementia Exercise report

Experts estimate that more than 24 million people worldwide suffer from dementia, a loss of mental functions including memory and ability to reason.  But there may be a way to reduce the chance of developing this disease.  VOA's Jim Bertel has more.

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Normal brain scan and brain scan indicating Alzheimer's  
  

The most common form of dementia is Alzheimer's disease.  There is no cure, and experts predict the number of cases of dementia will increase drastically in the coming decades, especially in developing countries.  Although the sufferers are mostly elderly, research shows dementia is not an inevitable part of aging.

Participants in a new study who exercised at least three times a week were nearly 40 percent less likely to develop Alzheimer's than those who did not exercise.  The lead researcher is Dr. Eric Larson says “the decline the brain experiences late in life is not inevitable.  It can be affected by things like habitual exercise."

  
  
All volunteers for the study were 65 and over and were subjected to memory tests.  Warren Raymond was one of more than 1,700 volunteers says the exercise has helped him. "It has not always been easy for me to exercise.  I'm just determined to do it. It enhances my self-esteem, improves my physical conditioning..."

In the study, exercise was anything from simple stretching to more vigorous activities such as swimming, walking, hiking, calisthenics, and weight training.  Dr. Larson says those who benefited the most were the frailest participants.

 
Dr. Eric Larson
  
But regular exercise is not a guarantee to ward off dementia.  During the six-year study, 158 of the participants developed dementia, but Dr. Larson says the exercise may slow the progression of this disease. 

Many other experts agree saying the link between exercise and dementia makes sense and is consistent with other studies.  They say exercise increases blood flow and oxygen to the brain, and it may reduce the "plaque" in the brain associated with Alzheimer's disease. 

One study involving mice compared the brains of mice put on a running wheel to those of sedentary mice.  It found the plaque, the large white spots seen in this photo was about a third less in the mice that exercised.  

Dr. Ron Peterson  
  
Dr. Ron Peterson directs Alzheimer's Research at the Mayo Clinic, says there is a correlation. "This lends some actual physiological support that there might be a direct mechanism between exercise and the development of plaques."

Experts hope more research will show if the kind of exercise, the intensity and the duration has any effect on slowing the progression or reducing the cases of dementia