To the Editor.
—The Special Communication by Dr Pate and colleagues1 provides an important message to sedentary adults. However, I believe that further explanation is required of their Figures 1 and 2 and the recommendation's contradiction with research that supports more vigorous activity.Their Figure 1 shows a diminishing return in health benefit with increasing exercise level. Measurement of the illustrated curvilinear plot shows a 12-fold greater health benefit from increasing physical activity status in sedentary individuals compared with physically active individuals. "Active" presumably means expending the caloric equivalent of walking 2 miles briskly most days of the week. It can mean no more than that for the horizontal x-axis to be linear, which is essential for the graph to have meaning. I am unaware of any data to support this substantial disparity in benefit. My own study of runners suggests that cardiovascular risk factors are improved as the
Williams PT. Physical Activity and Public Health. JAMA. 1995;274(7):533-534. doi:10.1001/jama.1995.03530070031016