VOA标准英语2011--Studies Show Exercise Reduces Dementia R

Studies Show Exercise Reduces Dementia Risk

Evidence continues to mount that physical exercise reduces a person's risk of dementia.
In some of the latest research, scientists measure actual physical activity, rather than rely on people's imperfect memories.
Most researchers studying physical activity and dementia rely on self-reporting. So they'll ask people in a study about what exercise they've had in the past week, for example.
But there are problems with self-reporting. Laura Middleton of the Sunnybrook Research Institute and the University of Waterloo in Canada says for one thing, people just don't remember what they've done. Also, people tend to report certain types of activities more than others.
"[Self-reporting] does a very good job of capturing jogging or biking or tennis, but does a relatively¹ poor job of capturing low-intensity activity like walking or daily chores, which may also be important to the risk of cognitive² impairment."
To get around that problem, Middleton measured physical activity with an established technique that uses doubly labeled water, made from isotope³ variants⁴ of hydrogen and oxygen. Participants in the five-year study drank a small amount of this special water, and by measuring the isotope variants in their urine, their energy expenditure⁵ can be calculated.
"What we found was a strong relationship between activity energy expenditure and the risk of incident cognitive impairment, she says, "with those of higher activity energy expenditure had 90 percent reduced risk of incident cognitive impairment over the follow-up period compared to those with very low energy activity expenditure."
Laura Middleton and her colleagues describe their findings online in the Archives of Internal Medicine, published by the American Medical Association.
In the same issue, another paper - this one from French researchers led by Marie-No?l Vercambre of the Foundation of Public Health in Paris - studied the exercise-dementia link in a large group of women with cardiac risk factors such as obesity⁶ or diabetes⁷. In this study, the women who got the equivalent of a brisk, half-hour walk every day had a lower risk of cognitive impairment.
Dr. Eric Larson of the Group Health Research Institute in Seattle, Washington, says the studies add to the evidence that physical activity can reduce the risk of cognitive decline.
"It's not obvious to people that exercise would make your brain healthier," he says. "And as each study does more detailed⁸ analyses of special groups or a different way of making the measurements, it just makes the scientific basis for this relationship a lot more convincing."
Larson writes that, with accumulating evidence of the link, research should now focus on how best to encourage people to be active, especially in later life.

1 relatively   

adv.比较...地，相对地

参考例句：

• The rabbit is a relatively recent introduction in Australia.兔子是相对较新引入澳大利亚的物种。
• The operation was relatively painless.手术相对来说不痛。

2 cognitive   

adj.认知的，认识的，有感知的

参考例句：

• As children grow older,their cognitive processes become sharper.孩子们越长越大，他们的认知过程变得更为敏锐。
• The cognitive psychologist is like the tinker who wants to know how a clock works.认知心理学者倒很像一个需要通晓钟表如何运转的钟表修理匠。

3 isotope   

n.同位素

参考例句：

• The isotope ratio is directly used for comparing oils or gases.同位素比率直接用于比较各种石油或天然气。
• How to apply a radio isotope?如何运用放射性同位素？

4 variants   

n.变体( variant的名词复数 )；变种；变型；（词等的）变体

参考例句：

• Those variants will be preserved in the'struggle for existence". 这些变异将在“生存竞争”中被保留下来。 来自辞典例句
• Like organisms, viruses have variants, generally called strains. 与其他生物一样，病毒也有变种，一般称之为株系。 来自辞典例句

5 expenditure   

n.(时间、劳力、金钱等)支出；使用，消耗

参考例句：

• The entry of all expenditure is necessary.有必要把一切开支入账。
• The monthly expenditure of our family is four hundred dollars altogether.我们一家的开销每月共计四百元。

6 obesity   

n.肥胖，肥大

参考例句：

• One effect of overeating may be obesity.吃得过多能导致肥胖。
• Sugar and fat can more easily lead to obesity than some other foods.糖和脂肪比其他食物更容易导致肥胖。

7 diabetes   

n.糖尿病

参考例句：

• In case of diabetes, physicians advise against the use of sugar.对于糖尿病患者，医生告诫他们不要吃糖。
• Diabetes is caused by a fault in the insulin production of the body.糖尿病是由体內胰岛素分泌失调引起的。

8 detailed   

adj.详细的，详尽的，极注意细节的，完全的

参考例句：

• He had made a detailed study of the terrain.他对地形作了缜密的研究。
• A detailed list of our publications is available on request.我们的出版物有一份详细的目录备索。