What Is RPE?

By now, you may have already heard iFIT Trainers mention RPE during running or biking workouts. What does RPE really mean, and how can you use it as a tool during your workout? Luckily, it’s relatively easy to nail down RPE and learn how to gauge how you’re feeling based on that scale.

Rate of Perceived Exertion, or RPE, is a numeric method of measuring your activity intensity level. Using a zero to 10 scale, RPE is entirely subjective and based on variables that change on a day-to-day basis. iFIT Trainers use RPE to help you try to put in the right amount of effort without shortchanging or overexerting yourself. Read on for more about RPE.

The origin of RPE

During the 1960s and 1970s, Swedish scientist Gunnar Borg pioneered the Rating of Perceived Exertion Scale. Borg’s 6-20 scale was designed to correspond directly with heart rates from 60 beats per minute (bpm) to 200 bpm.

At the lowest point on the RPE scale, a rating of six indicated “no exertion at all,” whereas a rating of 20 indicated “maximal exertion.” To use this scale, participants would rate their exertion level and then ramp up or slow their workout or movement. For example, during a quick power-walking session, your RPE could be a 12 on the Borg Scale. According to the above, you can determine your heart rate during this activity by  multiplying 12 by 10 for a heart rate of 120 bpm. This scale became incredibly popular as it served as an effective method of gauging heart rate during physical activity. Remember, this was long before heart rate monitors!

In 1986, Borg’s RPE scale was included as a “guide in monitoring and regulating exercise intensity” in the ACSM Guidelines for Exercise Testing and Prescription.

RPE today

Though Borg’s original RPE scale was incredibly useful in the late 20th century, it was modified as heart rate technology progressed. While the original Borg scale is used, more people gravitate toward a revised Borg scale called the Borg-Category-Ratio scale (CR10). This is what we use here at iFIT!

This scale is rated from zero to 10, with zero being “no effort” and 10 described as “maximum effort.” With this new scale, there is no heart rate math; it's entirely focused on perceived exertion, so it’s more simplistic. One of the great things about this scale is that it is dependent upon the individual. What feels like a four one day might feel like a seven another day, despite being the same exercise or movement. This is because factors such as sleep, hydration, stress, diet, injury, and more affect athletic performance. Maybe one day, you felt fantastic and had a great workout because of it. On another day, you didn’t have much water to drink, or you pulled a muscle the day before. Even if they may seem like minor issues, these variables can significantly impact your performance.

The revised CR scale allows you to stay within the bounds of moderate-intensity exercise without pushing yourself too hard. While you surely wish to give it your all, you also want to stay within a prescribed RPE when an iFIT Trainer calls out a four or five on the scale. To get the most out of your workout, you need to practice self-awareness here. How do you feel overall? What was your diet like before working out today? Did you sleep well? Questions like these are essential, as they’ll help you gauge where you fall on the RPE scale.

Another crucial aspect of RPE training is to be honest with yourself. If an exercise feels like an eight, don’t try to downplay how your body feels and call it a four. This could potentially lead to overexertion in the form of a strained muscle or other injuries. Instead, keep track of your RPE during every workout so that you can see linear progress. As you continue to put in the work, your RPE will show how far you’ve come!

Disclaimer: This blog post is not intended to replace the advice of a medical professional. The above information should not be used to diagnose, treat, or prevent any disease or medical condition. Please consult your doctor before making any changes to your diet, sleep methods, daily activity, or fitness routine. iFIT assumes no responsibility for any personal injury or damage sustained by any recommendations, opinions, or advice given in this article. Always follow the safety precautions included in the owner’s manual of your fitness equipment.