What was the purpose of the original Borg Scale of Perceived Exertion?

Oxygen consumption is estimated through metabolic testing or indirect calorimetry equations, not through a subjective perception rating.

Gunnar Borg created the RPE scale specifically to quantify the subjective sensation of fatigue and overall effort during exercise. The scale integrates feedback from muscles, joints, and cardiorespiratory systems to reflect the total sense of exertion. It serves as a practical, non-invasive tool for monitoring and regulating exercise intensity based on how hard the activity feels.

Blood pressure during exercise is measured directly with a sphygmomanometer; the Borg Scale has no mechanism for estimating systolic or diastolic values.

Intrinsic motivation is a psychological construct assessed by validated motivational questionnaires, not by a physiological exertion scale.