Argument154【0806G-永不言弃小组】第5次作业 by worldbaby

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154.The following appeared in the editorial section of a health and fitness magazine.
"In a study of the effects of exercise on longevity, medical researchers tracked 500 middle-aged men over a 20-year period. The subjects represented a variety of occupations in several different parts of the country and responded to an annual survey in which they were asked: How often and how strenuously do you exercise? Of those who responded, the men who reported that they engaged in vigorous outdoor exercise nearly every day lived longer than the men who reported that they exercised mildly only once or twice a week. Given the clear link that this study establishes between longevity and exercise, doctors should not recommend moderate exercise to their patients but should instead encourage vigorous outdoor exercise on a daily basis."
Argument 154【0806G-永不言弃小组】第5次作业 by worldbaby
Data: 2007-12-23  Words: 493   Time:16:52-17：29
syllabus:
(1)suspicious of the viladity of the survey
(2)there is no causal relationship between the longevity and exercise, other reasons may owing to the longevity
(3)such recommendation is not advisable for the people, the sexuality and the age should be taken into account.

Before recommend vigorous outdoor exercise to the patients instead of moderate exercise, the evidence given in the argument should be examined from several angles. The author assumed a link between the longevity and exercise based on the study. Close scrutiny of each step reveals that none of them can lead to the credible recommendation.
  In the first place, for the result to be accurate, it must be controlled, with the balance between the experimental and controlled groups. In the study above, we have no detailed information of the group, including the background, the general health before the study and even the climate of the parts involved in the research. On the one hand, if the men were in the different level of health before taking part in the study, it would different opinion in the frequency and the intensity of the exercise, for example, the people with heart disease apparently did not tend to engage in the vigorous outdoor exercise, which will definitely increase the risk of heart attack. Furthermore, the climate play a vital role in influencing people's outside exercise, for the part with wild weather, people are likely to exercise more those in the harsh climate. Without ruling out such possibilities that may lead to the inaccuracy of the study, the result obtained from the study is unconvincing.
  In the second place, even if we assume that the study is based on men of approximate character, there is no evidence that the clear link between the longevity and exercise exists. As it is a common sense that many other factors attribute to the longevity, such as eating healthily, live regularly, and dealing with pressure and relationship appropriately. Considering the preference of exercise, factors aforementioned may acts to more extent in influencing the longevity of people. Furthermore, even if the causal connection between longevity and exercise is true, it is insufficient to conclude that the people engaged in the vigorous outdoor exercise everyday lives longer than the men who exercised more mildly only once or twice a week. For example, weather and the health status will influence and even decide the frequency and the intension of the excise. So lacking detailed analysis of the factors concerning about the causal relationship, it is sheer folly to get the conclusion.
Finally, based on the conclusion above, the author suggested that the patient should take part in the vigorous outdoor exercise on a daily basis instead of moderate exercise. However, no evidence claimed to support such recommendation. For example, for patients who are bearing osteoporosis, a mild walk might be better choice. And also such suggestion is based on the study of men, women and children are excluded, furthermore, it is not safe to apply the advice to all the patients without consideration of the sexuality.
  In summary, the legitimate study should be controlled and also the validity of the suggestion should be revalued taking the difference among patients. The author fails to do that.

[ 本帖最后由 worldbaby 于 2007-12-24 23:26 编辑 ]