Rating of Perceived Exertion, or RPE, is one way of measuring the intensity of a workout. If you do not use a heart rate monitor, then it is the method to determine what intensity zone you are in, and where you need to be.
The Borg Rating of Perceived Exertion is a 1 to 20 scale; for our purposes, we will focus on the 6 to 20 range. The range was developed because it represents about 10% of the heart rate experienced by a moderately fit 20-something person. In other words, 6 = 60 bpm, or roughly a resting heart rate (no exertion), and 20 = 200 bpm, or maximum heart rate.
| RPE # | Breathing | Training Zone |
| 6 | No exertion | 1 |
| 7 | Almost nothing | |
| 8 | ||
| 9 | Very light | |
| 10 | Notice breathing deeper, but still comfortable. Conversations possible | 2 |
| 11 | ||
| 12 | ||
| 13 | Aware of breathing harder; more difficult to hold conversation | 3 |
| 14 | ||
| 15 | Starting to breathe hard & getting uncomfortable | 4 |
| 16 | ||
| 17 | Deep and forceful breathing, uncomfortable, don't want to talk | 5 |
| 18 | ||
| 19 | Extremely Hard | |
| 20 | Maximum Exertion |