Rate of perceived exertion (RPE)
Rate of perceived exertion (RPE) is a way of rating how hard an effort feels, most often on a scale from 1 (very easy) to 10 (maximal). It is a simple, surprisingly reliable guide to intensity that needs no device.
What the levels mean
On a 1–10 scale, 2–3 is easy recovery, 4 is a comfortable, conversational aerobic effort, 6 is moderately hard (short sentences only), 7 is comfortably hard threshold work, 8–9 is hard interval effort and 10 is all-out. The original Borg scale runs from 6 to 20, but the 1–10 version is easier to use.
When to use RPE
RPE responds instantly, unlike heart rate, and accounts for heat, hills, fatigue and terrain in a way pace can't. It's ideal for swim sets, trail running and days when you feel off. Pair it with power or pace once you have reliable thresholds, and use RPE as the check.
In The Next Race
The Next Race's plans use RPE on a 1–10 scale for swim and run efforts and as a guide alongside %FTP on the bike.