How to Use RPE to Improve Your Workouts

Thanks to smartwatches and fitness apps that track practically every health metric, it's easy to get caught up in the numbers — and forget to pay attention to how you feel — while you workout. One simple way you can keep tabs on your body? Turn to the rating of perceived exertion, or RPE, scale, which focuses on physical sensations that may crop up during exercise and clues you in on the intensity of your activity.

Here, trainers break down the meaning of RPE, share a common RPE scale and its benefits and pitfalls, and give tips on how to use the tool to your advantage.

What Is RPE?

Put simply, rating of perceived exertion is a tool used to measure the intensity of your workout or physical activity by tuning into your body, says Katie Fogelson, a MIRROR trainer and lululemon ambassador. Rather than definitive metrics, RPE is based on how hard you feel like your body is working, considering physical sensations such as increased heart rate, breathing rate, sweating, and muscle fatigue, according to the Centers for Disease Control and Prevention.

Though there are a variety of RPE scales to measure effort level, the most commonly used is a scale of 1 to 10, says Fogelson. Below, the trainer shares a breakdown of what these ratings mean.

RPE Scale

• RPE 1 to 3: Easy intensity. You can talk normally, breathe naturally, and feel overall comfortable.
• RPE 4 to 6: Moderate intensity. You can talk in short spurts, your breathing is more labored, but you're still working within your comfort zone.
• RPE 7 to 9: Hard intensity. You can barely talk, you're breathing heavily, and you're working outside your comfort zone.
• RPE 10: Max-effort intensity. You can't talk, you're gasping for breath, and you're working at your physical limit or past it.

The Benefits of RPE

The RPE scale may be simple, but it shouldn't be underestimated. For one, it can be a simple way to ensure you're scoring your weekly 150 minutes of moderate-intensity activity or 75 minutes of vigorous-intensity activity, as recommended by the U.S. Department of Health and Human Services. Specifically, you'll be hitting your moderate-intensity goals when your RPE is a five or six and your vigorous-intensity targets when your rating of perceived exertion is seven or eight, according to the D.H.H.S.

More importantly, determining your RPE can help you avoid burnout early on in your sweat sesh, says Morit Summers, a certified personal trainer and the owner of Form Fitness Brooklyn in New York City. "If my workout is 60 minutes, I can't give a hundred percent, get to that [RPE of] 10 within the first 10 minutes of my workout — then I've already given everything that I have and I can't get through the rest," she explains. "When I have this hour workout, I want to be able to stick anywhere from a six to an eight most of the time." By staying within that RPE range, you'll work up a serious sweat and feel challenged, but you're still able to finish the entire workout without feeling like you're dying, she says.

RPE also focuses on how you're feeling — not your heart rate, breathing rate, or pace, says Fogelson. Without the pressure of your fitness tracker metrics, you might feel more comfortable dialing back your workouts if your body is telling you to do so. "RPE's fluid approach to training intensity makes it easy to shift gears and keep pushing in the gym without being stuck to a rigid system," she says. "...No matter how fancy your fitness tracking device may be, it can't tell you how you feel."

The Shortcomings of RPE

The foundation of rating of perceived exertion is understanding how you're feeling in the moment. The problem? Many folks struggle to pinpoint just that, which can reduce the tool's accuracy, says Summers. "Some people don't realize how hard they go right off the bat…then other people are almost too nice to themselves and will be in the three-to-four range for the whole time," she explains. "If you are trying to work out harder or make progress in some way, you're going to need to push that [RPE] a little bit."

The tendency to overestimate exertion level is particularly common among fitness newbies and intermediate exercisers, and connecting with your body in this manner isn't a quick process, adds Fogelson. "Getting to know your RPE can take some time if you're a beginner and/or new to exercise in general," she explains. "Learning how to tune into your body is a skill that will improve over time and, as a result, so will your ability to determine the correct RPE."

Due to those potential drawbacks, Summers suggests viewing RPE simply as another tool to have in your pocket — not the only way to gauge your workout intensity. While lifting weights, you can also determine your exertion level by considering how many reps you're able to power through in a set compared to your goal. Say you pick up a set of dumbbells and are aiming to complete 10 reps of bicep curls. If you end up doing 25 reps without feeling too fatigued, your RPE might be a 3 and you could benefit from increasing that weight, says Summers.

Similarly, percentage training — determining load based on your true or estimated one-rep max — can clue you in on your intensity while pumping iron, adds Fogelson. For example, if your one-rep max for a deadlift (re: 100 percent effort, or a rating of perceived exertion of 10) is 100 pounds, a 70-pound deadlift would be at your 70 percent effort level (RPE of 7). "While RPE is more accessible in general, it is also subjective, which inherently makes it less accurate," she explains. "Percentage training removes the guesswork and allows you to track progress with very clear metrics."

During cardio-focused workouts, you can reference your heart rate to determine your effort level, says Fogelson. During moderate-intensity physical activity, your target heart rate should be between 64 percent and 76 percent of your maximum heart rate. For vigorous-intensity physical activity, it should be between 77 percent and 93 percent of your maximum heart rate, according to the CDC. Your heart rate is often easy to quantify and measure (thanks, smart watches) and generally matches up well with your RPE, says Fogelson. That said, "de-conditioned athletes tend to have higher resting heart rates, and the rate at which their heart rate will increase is faster, which doesn't always correspond to their RPE," she explains. "The more conditioned the athlete, the closer correlation between HR and RPE."

TL;DR: There's no one best way to measure your workout's intensity, so find a tool or two that's most effective and accurate for you.

How to Use RPE While Exercising

Ready to give the RPE tool a shot? Start by using it as a rough guide to adjust the intensity of your workout. "Generally speaking, if we were working out, we want to be a little uncomfortable, a little out of breath, sweaty, and feeling our muscles, so we're going to be at a five to eight [RPE]," says Summers. "If you feel like you're lower than that, you probably could pick it up a little bit."

Still, the exact rating of perceived exertion you're aiming for will depend on your fitness goals, says Fogelson. "If your goal is to build endurance for long-distance runs, more of your workouts will be spent in lower RPE ranges," she explains. "But if you're training for speed or sprinting-based runs, there will likely be a mix of high-intensity or high-RPE workouts."

In the latter instances, you'll want to be intentional of when, exactly, you hit an RPE of 10. If you're powering through 10 30-second sprints, hold off on hitting that rating of perceived exertion of 10 until your eighth or ninth sprint, says Summers. "If I start at a hundred percent, I'm not going to be able to do the rest of the sprints," she explains. While HIIT workouts often include short bursts of high-RPE exercises, make sure you hold off on your all-out, level 10 effort until the end of the sweat sesh, ensuring you're able to finish without feeling utterly exhausted right from the get-go, says Summers.

To make sure you're on track with your target RPE, head into your workout with a plan of how frequently you're going to check in with yourself — then stick to it. Consider asking yourself how you're feeling after every mile on a run, between every circuit of a HIIT workout, or after every set while you lift, suggests Summers.

And remember, "if you're new to RPE training, give it some time," says Fogelson. "And try to practice without using any gadgets, so you can truly tune in to your body and aren't swayed by what you're seeing on your watch."