What Does RPE Mean? Your Simple Guide to Measuring Workout Intensity

When I started lifting weights about three years ago, I had no clue what I was doing. And, having no personal trainer, I had to learn everything on my own — kind of.

I once ended up going to the gym with an old buddy of mine. Initially, the goal was for him to check my form. After completing a Romanian deadlift, he asked me about the RIR for that set.

“A what? Why do you talk abbreviations with me?” I blurted out, confused. Since then, many of these abbreviations have become a part of my daily vocabulary, e.g., RDLs instead of Romanian deadlifts — who has time to pronounce the entire thing?

Another abbreviation, RPE, or rate of perceived exertion, can be difficult for beginners to understand. To make your life easier, I have compiled information on what RPE means in fitness and how to use it to your advantage.

What does RPE mean?

In fitness, rated perceived exertion (RPE) measures how hard you push during exercise. The currently widely used scale rates the effort from 0 to 10, with 0 being the least effort or simply rest. This scale is also known as the Modified Borg CR10 RPE scale.

This scale does not use objective measures (e.g., heart rate), so it is highly subjective. Factors determining your RPE during exercise include effort, strain, discomfort, and fatigue.

Back to the beginning: the original Borg scale

Gunnar Borg developed the first RPE scale in the early 1960s, and it is still sometimes used today. The Borg scale ranges from 6 to 20; however, this unusual choice can be easily explained.

The Borg scale roughly correlates with one’s heart rate. To calculate, you should multiply the scale number by 10. For instance, if you believe that the exertion on the Borg scale would be 12, multiply it by 10 and cross-check with your heart rate readings. If it is around 120, you estimated accurately.

Given that this scale should correlate with one's heart rate, it may be limited by the varying heart rates due to age, medication, or other factors.

Beyond Borg: Modified Borg CR10 RPE scale

After the initial Borg scale, another scale was developed. In a way, it is a simplified version of the initial level of exertion scale. It is now widely used, and most people refer to it when using the term ‘RPE scale.’

This scale is also often used in weight lifting, while the initial Borg scale might work better for cardio training, where actual heart rate tracking is utilized more. However, both can be used for these purposes.

RPE vs. RIR: what's the key difference?

If you are looking for a scale for lifting weights, reps in reserve (RIR) is often preferred.

One reason why RPE might not be ideal for strength training is that scores can sometimes be lower, even when the maximum number of repetitions is performed. For instance, the athlete might rate their performance as very hard (7–9), although they lifted their 1RM (one rep max or the max weight you could lift at the given exercise).

Reps in reserve scale shifts the focus to how many additional repetitions you could still perform at the end of each set.

RIR-based RPE scale

For clarity, I will explain how to read and use this RIR chart.

For instance, if you see ‘6 reps @ 2 RIR’ in your training program, it means you have to perform six repetitions with a weight that would leave you two more repetitions in reserve.

If your program utilizes the RPE system, you will see ‘6 reps @ 8 RPE,’ meaning the effort level should be at RPE 8 on a scale of 1 to 10.

In other words, RIR and RPE could be considered quite similar: both help you monitor your efforts. Additionally, they both correlate and can be transferred from one system to another.

Kristina Turnure, a women’s health and fitness expert with a master’s degree in exercise physiology, likes to blend both in her practice. She gives an example of how she would explain how one’s body feels to her client:

“This should feel like a 7/10, meaning you have three reps left. If you’re aiming for 10 reps, you should be able to go for 13 so that we have room to increase weight and intensity as the program progresses over time.”

How is RPE applied in strength training?

In strength training, many programs rely on the level of exertion to adjust training loads. Coaches and trainees can set training loads based on RPE to ensure they are lifting at the desired intensity.

RPE also comes in when devising a program based on your personal goals.

Looking at the figure, you can see how you could adjust your reps per set count. For instance, if muscle growth is your priority, aiming to do 7 to 12 reps per set is recommended. If you feel like you do not reach an RPE of 7 to 10 on the set, you can increase the weight. For strength, on the other hand, you would want to have higher weights — but do fewer reps.

How is RPE applied in cardio?

The RPE scale can also assess your exercise intensity for cardio workouts.

For example, if a runner aims to build endurance, they might target an RPE of 5 to 6 on a scale, indicating a moderate intensity where they can maintain a conversation but still feel challenged.

If the effort feels too easy (an RPE below 5), they may need to increase their pace or resistance to achieve the desired training effect.

Is the RPE scale an accurate assessment of exercise intensity?

The RPE scale is accurate, and various studies support the correlation between the perceived exertion level and physical signs of exertion.

Research has shown strong links between RPE ratings and physiological markers such as heart rate, oxygen consumption (VO2), and blood lactate levels. This means that when individuals rate their effort on the level of exertion scale, it generally reflects their actual physical workload.

However, the scale relies on subjective input, meaning that some trainers might not be able to gauge their efforts correctly. For instance, beginners might struggle as they don’t have experience yet, and similarly, extremely fit athletes could sometimes be off because they are already adjusted to discomfort.

Final thoughts

RPE can be a valuable tool in your fitness routine for tracking effort, guiding training, and listening to your body. It can be used to self-regulate, improve progress, and reduce the risk of muscle fatigue and injury.

I personally do not purposely track RPE in my training program, but I adjust my exercises based on factors other than effort and fatigue. The amount of reps and weight I lift can vary based on various factors, but being seasoned in the gym, I have some understanding of when I can push harder. In a way, I apply RPE without using the RPE scale.

As I started lifting weights without professional guidance, I was introduced to the RPE scale rather late. I did not see it as essential for monitoring my load, as I learned to do it intuitively.

Keep in mind that lifting weights is not dangerous per se, but lifting mistakes can be costly, and injuries can be hard to rehabilitate. Thus, you should consider working with a trainer.

Your personal trainer can guide and teach you how to use RPE (or suggest other tools, such as percentage-based training). However, this does not mean that you can’t include RPE in your program on your own — but remember, it can take time to master this skill.

Lastly, while including the level of exertion tracking in your training may help you optimize your exercise, it can also be overwhelming, especially when starting out. I would suggest focusing on the consistency of your training first and only then trying to learn RPE if you see it fits your goals.