Chad Boehm Chad Boehm

Measuring Intensity Series, Part 1: Rating of Perceived Exertion

What is RPE and how can you use it to supplement your measure of intensity?

When exercising, the FITT principle dictates we must consider the Frequency, Intensity, Time and Type of exercise being performed. When developing fitness, the two most important factors are Time and Intensity. When measuring intensity we have a few options. Most often, one will see plans based on pace or heart rate, but power is becoming more popular, recently. A measure of intensity we don’t see super often, but is a really great adjunct to the others, is Rating of Perceived Exertion, or RPE.

RPE or your “Rating of Perceived Exertion” is a subjective measure of how hard you are working. This is indicated by the “Perceived” portion of the name; what is your perception of your effort? For example, you and a training partner may be running the same pace at the same heart rate, but it feels “moderate” for you and “hard” for your training partner.

You might be thinking, “Well, what’s the use in that? Don’t I want objective data to tell me how hard I’m working?” That is partially correct. We do want objective numbers (heart rate, pace, power) that give an indication of how hard we are working, relative to a given anchor point (maximum heart rate, functional threshold power, velocity at VO2max, etc). BUT, those numbers only tell part of the story. Working at 80% of FTP might feel “hard” some days and “moderate” other days and possibly even “easy” while tapering. To paint a clearer picture of a workout, it’s best to use a mix of subjective (how you feel) and objective (how hard you’re working) measures.

“But, if this whole thing is subjective, how does one achieve consistency?” Through practice! Every workout, take periodic checks and ask yourself, “How hard does this feel? Does the ‘easy’ effort prescribed actually feel easy? Or do I feel like I’m working kind of hard?” Over time, you will develop an intuition for how hard you are working. You may do this by assessing things like posture (“Are my shoulders drooping?”), breathing (“Is my breathing labored?”) or fatigue (“Are my legs heavy?”). The more you practice assigning an RPE value to your effort, the more consistent you will become in estimating your effort by feel. And that’s one of the major reasons I like RPE as an adjunct to objective measures; by its nature, it encourages one to become introspective during an effort. 

“Okay, this sounds great and all, but what do you mean, when you say ‘assign an RPE value’? Like, where do these magic numbers come from?” That’s a great question! There are a number of RPE scales out there. If you Google it, you’ll most likely get a 10-point scale:

One to ten RPE scale

Classic 1-10 scale

Or the Borg RPE scale:

Borg RPE scale

You’re probably asking yourself, “Six to 20? Why on Earth would someone use 6 to 20?” I know I did the first time I saw this thing.

Me, the first time I saw the Borg scale

Turns out, there was a method to this mayhem. Dr. Gunnar Borg, Ph.D., MD, a psychiatrist from Sweden, developed this scale in the 1960’s. The idea being, if you multiply each number by 10, it would correlate to a heart rate at that RPE. In other words, a person working at 150 bpm would report an RPE around 15. While this might hold true for a percentage of the population, the heart rate thing is more of a “fun fact” than a “tried and true” correlation. 

The main point to consider is that an RPE scale can come in many forms. Here are a few I’ve seen used in the past:

  • A two-category scale: 

    • Easy

    • Hard

    • That’s it. May work with very polarized training, but we tend to work in more varied intensity ranges than just ‘hard’ or ‘easy’.

  • A  three-category scale. “General Running Endurance” (GRE) intensities are defined as:

    • GRE I: Easy running. Recovery runs.

    • GRE II: Moderate running. Aerobic training. Around half marathon or marathon pace.

    • GRE III: Hard running. Anything from threshold work to longer reps on the track or VO2 work.

  • A four-category scale:

    • 1. Easy: Recovery runs

    • 2. Aerobic: Long runs

    • 3. Threshold: Tempo runs

    • 4. Anaerobic: Speed work

  • A five-category scale based mostly on breathing

    • 1: Light running. Can speak full sentences. Breathing is a little deeper and a little more frequent than resting.

    • 2: Moderate running. Can still speak in full sentences. Breaths are becoming deeper, but not much more frequent.

    • 3: Threshold running. Can get out a few words at a time. Breaths are becoming deep and frequent. 

    • 4: VO2 running. One word at a time. Breathing is labored. Deep, fast breathing.

    • 5: Anaerobic Reps: Unable to speak; maybe a word at a time. Struggling to breathe. Breaths are very frequent and shallow.

Personally, I tend to use a four or five category classification. I find it a bit easier to identify shifts in effort as one increases intensity. In our programs, we tend to use a 10-point scale, mostly because this is easy to conceptualize for most people; 1 is easy, 10 is hard. 

Okay, so you’ve decided to use a 1-10 RPE scale. How does one use it in practice? Well, if someone is new to running, or doesn’t have a heart rate monitor, I will often let RPE guide the workout. Take the Cooper 12 Minute Run Test, used to assess fitness at the start of a program, but guided by RPE.

  1. Ramp up in 4 steps

    1. 400 m @ 3-5 RPE

    2. 400 m @ 4-6 RPE

    3. 400 m @ 5-7 RPE

    4. 400 m @ 6-8 RPE

  2. Walking Recovery
    3 min @ 1-2 RPE
    Get to start line

  3. Repeat 4 times

    1. Hard
      100 m @ 7-10 RPE

    2. Easy
      1:30 @ 1-2 RPE

  4. Active
    12 min @ 7-9 RPE
    Aim for consistency!

  5. Cool Down
    400 m @ 1-2 RPE

Again, if someone is new to running, this is going to be a bit of a guessing game to start with. But after a workout like this, where an athlete runs through a variety of intensities, they should have a very good starting point to start applying RPE to their daily running.

While objective metrics like heart rate, pace, and power have their place, RPE offers a unique insight into the subjective side of your workout experience. It's the bridge between the numbers and your effort.

By incorporating RPE into your fitness routine, you can fine-tune your training and prevent overtraining by listening to your body and making adjustments accordingly. Remember, our bodies don't always adhere to a strict numerical code. Some days, an 80% effort might feel harder than other days. With RPE, you can adapt and ensure that every workout aligns with your current fitness.

So, start incorporating RPE into your training sessions. Pay attention to how your body feels during workouts, and assess your effort on a scale of 1 to 10. Over time, you'll develop an intuitive understanding of your exertion. With RPE, you'll be able to train more effectively, reduce the risk of overtraining, and ultimately make more significant strides towards your fitness goals. Your body will thank you for it.

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