Where RPE Originated: RPE is actually an updated (and simpler) take on the original Borg Rate of Perceived Exertion scale, which went from six to 20 and was much more correlated with heart rate ...

If you’ve never heard of RPE before, it simply stands for Rate of Perceived Exertion. Or to put it another way, it's how fatigued you are or how intense an exercise feels during any given ...