A numerical value is given to subjectively rate the level of exertion. Rating of Perceived Exertion (RPE) is a scale devised by Dr. Gunner Borg to be used by the fitness class participant to rate the student’s perception of exercise intensity on a 10-point scale. (Range: 1 = Very light / 10 =Very hard). A client should exercise between an RPE of 4 (strong) and 5 or 6 (very Strong)