Rating of perceived exertion

In sports, health, and exercise testing, the rating of perceived exertion (RPE), as measured by the Borg rating of perceived exertion scale,  is a quantitative measure of perceived exertion during physical activity.

In medicine, this is used to document the patient's exertion during a test for the severity of diseases. Sports coaches use the scale to assess the intensity of training and competition as well as endurance. The original scale introduced by Gunnar Borg rated exertion on a scale of 6-20. Borg then constructed a newer category-ratio scale, the Borg CR-10 scale, rated on a scale from 1-10. This is especially used in clinical diagnosis and severity assessment of breathlessness and dyspnea, chest pain, angina and musculo-skeletal pain. The CR-10 scale is best suited when there is an overriding sensation arising either from a specific area of the body rather than overall exertion, for example, muscle pain, ache or fatigue in the quadriceps or from pulmonary responses during exertion.

The Borg scale can be compared to other linear scales such as the Likert scale or a visual analogue scale. The sensitivity and reproducibility of the results are broadly very similar, although the Borg scale may outperform the Likert scale in some cases.

Borg RPE scale
The Borg RPE scale is a numerical scale that ranges from 6 to 20, where 6 means "no exertion at all" and 20 means "maximal exertion." When a measurement is taken, a number is chosen from the following scale by an individual that best describes their perceived level of exertion during physical activity.

The scale was constructed to roughly correlate to 10% of heart rate in a healthy 20-year-old. In older individuals, the correlation becomes higher than 10% at the high-end of the scale, as maximum heart rate declines with age.

Borg RPE scale and the external environment
It appears that outdoor enternal environments can lower the perceived exertion that a given exercise is connected to in laboratory or other indoor conditions.



CR-10 scale
Borg later developed a CR10 scale.