It is generally believed that people need to engage in regular and strenuous physical exercise in order to maintain their physical health. Actually, however, low-impact walking—that is, walking at a normal pace, which elevates the heart rate and releases many of the hormones released in more strenuous exercise—is enough. This is evidenced by the strong correlation between the amount of time spent walking and measures of general physical health demonstrated by many studies.
Which of the following, if true, most seriously weakens the force of the evidence cited?
【选项】
Most doctors advise that people begin more strenuous and intense physical exercises if they wish to improve their conditioning.
选项是否正确？