What Is RPE and How Do You Use It to Train by Feel?

If you have just started running, or you are returning to running after a break, you may have come across training plans that prescribe sessions by pace, by heart rate zone, or by something called RPE. Pace and heart rate both require a watch. RPE does not. It requires something you already have and use constantly without thinking about it: your own judgement of how hard you are working.

This post explains what RPE is, how the scale works, and how to use it to train effectively as a beginner. If you have purchased the Barbour Performance Systems Beginner 5k Training Plan, this is the guide that explains the intensity targets in that plan and how to apply them in practice.

What RPE Actually Is

RPE stands for Rate of Perceived Exertion. It is a simple numerical scale that describes how hard an exercise effort feels, from very easy through to maximum. Rather than measuring what your body is doing through external data - pace per kilometre, heart rate in beats per minute - RPE captures your subjective experience of the effort. How hard does this feel right now?

The concept was developed by Swedish psychologist Gunnar Borg in the 1960s and has been used in exercise science and sports medicine ever since. The original Borg scale ran from 6 to 20, calibrated roughly to heart rate when multiplied by 10. A more intuitive simplified version - the one used throughout this guide - runs from 1 to 10.

What makes RPE valuable is that it integrates everything that affects how hard exercise feels. Pace alone does not account for heat, hills, fatigue, poor sleep, or whether you are at sea level or altitude. Heart rate alone does not account for cardiac drift, medication, or the daily variation in how your body is responding to training. RPE accounts for all of it, because it is your body's complete read of the situation, not one isolated variable.

This makes it particularly useful for beginners, who may not yet have the running history to know what a given pace feels like, and whose heart rate response to exercise is still establishing its individual baseline.

The 1-10 RPE Scale

Here is how the simplified 1-10 scale works in the context of running:

RPE 1-2: Extremely easy. Standing, walking slowly, barely any exertion. Not relevant for running.

RPE 3: Very easy. A very slow walk or the easiest possible jog. Breathing is completely unconstricted. You could hold a full, relaxed conversation without any effort.

RPE 4: Easy. A comfortable, relaxed jog. Breathing is slightly deeper than at rest but entirely unforced. You can hold a full conversation without pausing for breath. This should feel almost embarrassingly easy if you are used to running at a moderate effort.

RPE 5: Moderate. A comfortable aerobic effort. You are working noticeably but not straining. You can still hold a conversation, though you might prefer shorter sentences. This is the upper boundary of genuinely easy training.

RPE 6: Moderately hard. The effort is becoming meaningful. Full conversation is possible but requires some concentration. This sits at the lower end of what most runners would call a steady run.

RPE 7: Hard. Breathing is noticeably elevated. You can speak a few words but not comfortably hold a conversation. This is threshold effort - the boundary between aerobic and increasingly anaerobic exercise. This is where a structured interval or tempo session operates.

RPE 8: Very hard. Speaking is limited to brief phrases. This is close to race effort for a short distance - near the top of sustainable intensity. Not something most beginner runners will use in training.

RPE 9: Extremely hard. Barely able to speak. Near-maximum effort that can only be sustained briefly. Reserved for very short, very intense intervals.

RPE 10: Maximum. Absolute maximum effort. Unsustainable beyond a few seconds. Not used in regular training.

For a beginner 5k programme, the vast majority of sessions sit between RPE 4 and RPE 6. Occasional more structured efforts may reach RPE 7. You should not be training at RPE 8 or above in the early weeks of any beginner running programme.

Why Easy Runs Feel Harder Than They Should

This is one of the most important practical points for any runner new to structured training: genuinely easy running is slower and more comfortable than most people expect.

When you first start running, any running feels like hard work. As fitness develops over the first few weeks, the same effort feels progressively easier. But there is a persistent tendency - even among experienced runners - to run easy sessions at a moderate effort (RPE 5-6) rather than a genuinely easy effort (RPE 4). The difference might only be 30 to 60 seconds per kilometre, but physiologically it is significant.

Running every session at a moderate effort generates more fatigue than it needs to, without producing the specific aerobic adaptations that genuine easy running provides. It also leaves you less recovered for the days when the plan asks you to work harder.

If an easy session feels almost too easy - if you find yourself thinking you could push a bit more - that is usually a sign that you are running at approximately the right effort. Easy running should feel sustainable for a very long time. It is not a warm-up. It is the session.

How to Use RPE in Practice: The Conversation Test

The simplest real-world calibration for RPE is the conversation test. Can you hold a comfortable, flowing conversation while running? If yes, you are at RPE 4-5 and within the easy training range. If you can speak but would prefer not to, you are at RPE 6. If conversation requires genuine effort, you are at RPE 7. If you cannot hold a conversation at all, you are at RPE 8 or above.

You do not need a training partner to use the conversation test. Many runners simply narrate their run internally - a running commentary on what they can see, where they are, what they are thinking. If that internal narration flows without interruption from breathing demands, the effort is appropriately easy. If it is regularly interrupted by the need to breathe, the effort is too high for an easy session.

Another reliable calibration: can you breathe predominantly through your nose? At genuinely easy efforts - RPE 4 to 5 - most people can breathe through the nose for extended periods, though this varies with individual anatomy. The moment you feel compelled to open the mouth to breathe, the effort has moved toward RPE 5-6. This is not a hard boundary, but it is a useful awareness signal.

RPE vs Pace: Which Should You Use?

Pace is a useful reference, particularly as you develop experience and a personal pace library - an understanding of what different efforts feel like at different paces in different conditions. But pace has limitations that make it unreliable as the sole intensity guide, particularly for beginners.

Pace does not account for terrain. Running at 6:30/km on a flat road and running at 6:30/km up a hill are very different physiological efforts. Pace does not account for conditions - running at 6:30/km in 8°C is easier than running at the same pace in 22°C. Pace does not account for how you feel - running after a good night's sleep is physiologically different from running after disrupted sleep, at the same pace.

RPE absorbs all of these variables automatically, because it is measuring the integrated experience rather than one external parameter. For a beginner who does not yet have an established pace library, this makes RPE the more appropriate primary intensity guide. As you develop more experience, pace and RPE work best together - pace as the reference, RPE as the check.

Why RPE Works as a Long-Term Skill

Learning to run by feel is not just useful for beginners. It is one of the most valuable skills an endurance runner can develop at any stage of their career. Athletes who have a well-calibrated sense of effort are better at pacing races, more able to adapt to conditions, and less dependent on technology to execute their training correctly.

A GPS watch is a useful tool. Heart rate monitoring adds genuine value. But an athlete who can only train and race effectively when tethered to a device has a dependency that will eventually cause a problem - a flat battery, a failed sync, a lost signal in a tunnel at kilometre 17. The athlete who knows what RPE 7 feels like in their own body, independently of any device, is operating with something more reliable than technology.

Building that internal calibration starts here, at RPE 4 on an easy Tuesday morning, when the effort feels almost too easy and every instinct says to push a little harder. That instinct is worth resisting. The athlete who learns to resist it - who learns to trust the easy effort, to run within themselves, to measure output by feel rather than by ego - is the one who builds sustainable fitness and races well.

Key Takeaways

RPE is a 1-10 scale of perceived effort that allows you to train by feel rather than by pace or heart rate. For beginner runners, it is the most practical and flexible intensity guide available. Easy sessions should sit at RPE 4-5 - comfortable, conversational, and slower than your instincts may suggest. The conversation test is the simplest real-world calibration. Pace and heart rate are useful companions to RPE, not replacements for it. And learning to judge your own effort accurately is a skill that will serve you across every stage of your running career.

If you have any questions about how the intensity targets in your plan translate to your specific pace or heart rate as you build fitness, the weekly check-in is the right place to raise them. The numbers are a guide. Your experience of the effort is the data.

Steve Barbour is a UK-based online running and triathlon coach. For free training and race calculators, visit endurancetoolkit.com.