[Evaluation of Borg's perceived exertion scale in cardiac rehabilitation].

Borg's perceived exertion scale measures the extent of perceived exertion which a person experiences during exercise. The perceived exertion scale is used to adjust exercise intensity (workload) for predictions and prescriptions of exercise intensities in sports and medical rehabilitation (BORG, 1982). In addition, Borg's scale can be used in the athletic arena, space, industry, military settings, or under everyday circumstances. The concept of perceived exertion is a subjective rating, indicating the subject's opinion about the intensity of the work being performed (MORGAN, 1973). The task of exercising subjects is to assign a number (from 1-20) to represent the subjective sensation of the amount of work being performed. This is a valuable tool in human performance setting, where an important consideration is not "what the individual is doing, but what he thinks and is doing" (MORGAN, 1973).