In exercise, managing training intensity is critical for improving performance, reducing injury risk and optimising recovery. One of the most practical and widely used tools for this is the Rate of Perceived Exertion (RPE) scale.
Originally developed by Swedish psychologist Gunnar Borg, RPE provides a subjective measure of exercise intensity that closely correlates with physiological markers such as heart rate, blood lactate and oxygen consumption.
What is RPE?
RPE is a subjective rating of effort, typically measured on a 1–10 scale in resistance training contexts (a simplified adaptation of Borg’s original 6–20 scale).
Each number reflects the overall stress experienced by the body, integrating signals from:
The cardiovascular system
Muscular fatigue
Respiratory strain
Central nervous system load
Simplified RPE Scale (1-10)
1–2: Minimal exertion
3–4: Light effort
5–6: Moderate intensity
7–8: Vigorous effort
9: Near-maximal
10: Maximal exertion (volitional failure)
The Science Behind RPE
Research in exercise physiology shows that RPE is strongly correlated with:
- Heart rate (HR)
- Blood lactate accumulation
- VO₂ (oxygen uptake)
- Motor unit recruitment
In resistance training, RPE is also closely linked to “repetitions in reserve” (RIR)- which we will talk about in a future blog post!
RPE 10: 0 reps left (failure)
RPE 9: ~1 rep in reserve
RPE 8: ~2 reps in reserve
RPE 7: ~3 reps in reserve
This relationship allows for precise load regulation without requiring maximal testing.
Why RPE Is Effective For Clients
Unlike fixed percentage-based training (e.g., % of 1RM), RPE is autoregulatory, meaning it adjusts to daily fluctuations in performance capacity.
These fluctuations can be influenced by:
- Sleep quality
- Nutritional status
- Psychological stress
- Training fatigue
Auto-regulation is supported by research as a method to improve training outcomes while reducing the risk of overtraining and injury.
Practical Application In Training
A trainer might prescribe:
👉 “3 sets of 8 reps at RPE 7–8”
This ensures:
- Sufficient intensity to stimulate adaptation
- Avoidance of unnecessary fatigue accumulation
- Consistent training quality across sessions
Rather than chasing a fixed load, the client adjusts weight to match the target physiological effort.
RPE & Progressive Overload
RPE allows for more nuanced progression models:
- Load progression: Increasing weight at the same RPE
- Volume progression: Increasing reps or sets at the same RPE
- Intensity progression: Gradually working at higher RPEs
This aligns with key principles of progressive overload while maintaining fatigue management.
Limitations of RPE
While highly useful, RPE is not without limitations:
- Requires experience and body awareness
- Can be influenced by motivation and pain tolerance
- Less accurate in beginners
However, accuracy improves significantly with coaching and repeated exposure.
Final Thoughts
RPE is a scientifically grounded, flexible method for prescribing and monitoring training intensity. By integrating both physiological and psychological factors, it provides a holistic measure of effort that enhances individualisation in training programmes.
For clients, learning to use RPE effectively is a key step toward developing long-term autonomy and optimising results.
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