Using RPE for Exercise Intensity

Another method for prescribing and monitoring exercise intensity involves using ratings of perceived exertion (RPE). Perceived exertion refers to the physical strain individuals believe they are experiencing while exercising. Perceived exertion feedback is important because it provides a practical means for individuals to become sensitive to what constitutes appropriate exercise intensity. During exercise, perception of effort is influenced by a variety of cues — some local in nature (e.g., sensations of muscular discomfort or strain) and some central in nature (e.g., heart rate, breathing rate, etc.).

The most common measurement tool for assessing perceived exertion is a ratings scale named after its developer, Swedish psychologist Gunnar Borg. Borg’s pioneering concepts involving perceived exertion have evolved dramatically over the years. Originally, Borg proposed a scale (also referred to as the RPE Scale) that utilized 15 categories (6 to 20) of sensations — seven of which were identified by descriptors (refer to Table 1).

Borg’s original efforts were based on the premise that his numbering system closely correlated to heart rate. When a “0″ was added to each category number, a range of numbers comparable to the heart rate range in young, trained individuals (60 to 200 bpm) was created. Borg’s initial RPE scale followed the patterns of heart rate and oxygen consumption during incremental aerobic exercise. As exercise intensity increased, heart-rate, oxygen consumption and RPE increased. Subsequently, however, Borg and other exercise scientists recognized that perceived exertion is extensively influenced by additional variables, some of which have a nonlinear relationship to exercise intensity (e.g., lactic acid production, ventilatory responses, etc.). As a result, in the early 1980s Borg developed a new scale with ratio properties (refer to Table 1).

In the more than 20-year period since Borg introduced his original work on perceived exertion, RPEs have been found to have a wide range of applications. Probably the most common use of RPEs involves monitoring exercise intensity. The individual who is exercising provides a verbal description of how (relatively) difficult the exercise is based on categories assigned to each of the numbers. For example, a perceived exertion rating of 4 of the Category/Ratio RPE scale has been observed to correspond to approximately 60 percent of V02max. On the other hand, a rating of 6 corresponds to approximately 80 percent to 85 percent of V02max. Therefore, an RPE range of 4 (somewhat strong) to 6 (strong) is recommended for most healthy adults.

Monitoring exercise intensity with the RPE scale is beneficial because:

* It serves as a cross-check on THR, especially if estimations of maximal HR are based on age.

* Unlike HR monitoring, you’re not required to stop exercising to check it.

* It requires no special equipment to accurately describe your perception of intensity, whereas relatively expensive HR monitors are needed for accurate HR determinations.

A number of studies have shown that participants skilled at using RPE as an indicator of overall feeling of exertion can use it to easily and effectively specify an RPE level to achieve a particular level of conditioning.

It can also be used in conjunction with a THR prescription. In addition, RPE can be used to assess (and modify, if necessary) the effectiveness of a specific exercise prescription. RPE, for example, is often one of the first readily recognizable measures of (positive) changes in aerobic fitness.

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