performance metrics
Rate of Perceived Exertion (RPE)
How it works, and how cyclists can use it alongside or instead of power for smarter training.
What It Is
Rate of Perceived Exertion (RPE) is a subjective scale that measures how hard exercise feels to you. Commonly using a 1–10 scale, RPE accounts for breathing rate, muscle fatigue, mental effort, and how sustainable the effort feels.
Even with modern tech like power meters and heart rate monitors, RPE remains one of the most reliable ways to gauge intensity, especially when conditions or equipment vary.
ELI5 Version
RPE is your internal effort meter. Instead of numbers from your bike computer, it’s you asking, “How hard does this feel?”
Why It Matters
- Works anytime, anywhere, even without sensors or devices.
- Captures internal load, which power and heart rate don’t fully reflect.
- Essential for pacing, especially in long events.
- Helps calibrate training zones by aligning feel with data.
- Reliable during bad conditions (heat, fatigue, altitude), when numbers lie.
- Improves intuitive pacing, a key skill for endurance athletes.
Practical Use
- Use an RPE 1–10 scale to understand session goals:
- RPE 2–3 → Endurance (Z2): here is a good example of what that looks like from Peter Attia
- RPE 4–6 → Tempo/Sweet Spot
- RPE 7–8 → Threshold
- RPE 9–10 → VO₂ Max & Anaerobic
- Cross-check RPE with power, heart rate, and Max HR to keep training zones honest.
- Use RPE on days when power drifts (heat, stress, fatigue).
- Build pacing intuition by noting RPE during interval sessions.
- Quickly adapt workouts by adjusting power targets when RPE is unusually high or low.
Power zones and heart rate are just another way to estimate what is happening in the body. RPE serves the same purpose.