RPE: What Is It and How Can We Use It?

What Is the RPE Scale?

An RPE scale is a numerical scale that’s used to convert your subjective feelings about how hard you’re working into an objective number.

High numbers on the RPE scale represent exercising at or close to maximum effort, and low numbers represent exercising at a low intensity (like walking). 

The two most commonly used RPE scales are the Borg RPE scale and the Modified RPE scale. Let’s look at each separately.

The Borg RPE Scale

The Borg RPE scale, also known as the “Borg RPE scale 6-20” is named after Gunnar Borg, a Swedish researcher who introduced the concept of the RPE scale in several studies published in the 1950’s.

The 15-point Borg RPE scale ranges from 6-to-20, with 6 representing no exertion or rest, and 20 denoting maximum exertion or complete exhaustion. 

Here’s how it looks:

The Borg RPE scale goes from 6-to-20 because if you multiply those numbers by 10, you’ll get a rough estimate of what your heart rate will be at each level of intensity, which is a reliable indicator of cardiovascular exertion.

For example, if your run feels like a 10 RPE your heart rate is probably in the ballpark of 100 beats per minute.

That brings us to one of the drawbacks of the original Borg RPE scale: it’s designed for cardio workouts, not strength workouts, where heart rate isnr closely correlated with physical effort.

There are three other downsides to the original chart:

It can be difficult to determine exactly where you fall on the scale without practice because it offers so many options (“am I at 15, 16, or 17?”).

Studies show that heart rates can vary quite a bit person-to-person at the same workout intensity. That is, two people of a similar size who are running at the same pace might have very different heart rates. 

All that is why Borg eventually developed a more universally practical RPE scale known as the Modified RPE scale.

Modified RPE Scale

The Modified RPE scale, also known as the “CR10 RPE scale” or the “RPE scale 1-10,” is a 10-point scale that can be used to measure many kinds of perceptions, sensations, and subjective experiences, including perceived exertion, pain, and dyspnea (breathlessness).

There are many different version of the Modified RPE scale floating around the internet, but they all look more or less like this.

Unlike the original Borg scale, the Modified RPE scale is simple and intuitive. Most people can quickly understand what a 1, 5, or 10 feels like without extensive practice, making it easier to use during both training and competition. Because it focuses on perceived effort rather than heart rate, it can be applied to a much wider range of activities, including strength training, cycling, running, rowing, and team sports.

In the context of strength training, an RPE rating is often used to estimate how many repetitions an athlete has left “in reserve” at the end of a set. For example, an RPE 10 set represents maximal effort with no additional repetitions possible, while an RPE 9 set indicates that one more repetition could probably have been completed. An RPE 8 suggests roughly two repetitions remained in reserve, and so on. This approach allows lifters to adjust training intensity based on their daily readiness and performance rather than relying solely on predetermined weights.

One of the main advantages of the Modified RPE scale is that it encourages autoregulation—the practice of adjusting training intensity based on how your body feels on a given day. Factors such as sleep quality, stress, nutrition, recovery, and environmental conditions can all influence performance. By using RPE, athletes can account for these variables and train at an appropriate intensity even when their performance differs from expectations.

That said, RPE is still a subjective measure and becomes more accurate with experience. Beginners often struggle to accurately judge how close they are to their maximum effort, particularly during strength training. However, research and practical experience show that as athletes gain training experience and become more familiar with their physical limits, their RPE ratings tend to become increasingly reliable and useful for guiding training decisions.