Exercise intensity is one of the most important variables that determines the effectiveness of a workout. As a result, most workouts express the target intensity by power output, heart rate, pace, and RPE. What does RPE mean? Rating of Perceived Exertion, or RPE, is the simplest of all ways to gauge exercise intensity. It is simply a subjective measurement of how hard you feel you are going. In an age when athletes have access to an expansive array of data from training devices, wearables, and apps, RPE seems quaint and unsophisticated. To the contrary, it is surprisingly accurate, even in the face of variables that render device-based measurements useless.
Athletes and coaches typically use one of two RPE scales: the Borg Scale from 6-20 or a simpler 0-10 scale. In either scale, the harder your effort, the higher the RPE value. There’s not one single piece of data collected and you don’t need any special equipment. All you need is the scale.
To Borg or Not to Borg?
The scale CTS Coaches use in the physiology lab is the Borg Scale, which ranges from 6 to 20 (6 being no exertion at all and 20 being a maximum effort). Why 6 to 20? Well, Borg’s research has shown a high correlation between the number an athlete chooses during exercise, multiplied by 10, and his or her actual heart rate at that time.
In other words, if you’re on an ergometer during a lactate threshold test and say you feel like you’re at 16, there is a pretty good chance your heart rate is around 160 beats per minute. This isn’t absolutely true of all athletes, but you’d be surprised how accurate the 6 to 20 scale tends to be.
Outside the lab, however, the 6-20 Borg Scale isn’t very intuitive for athletes. Most athletes find it easier to relate to a simpler 0 to 10 scale (0 being no exertion at all and 10 being a maximum effort). Under this scale, an endurance or “cruising” pace would be a 4 to 5, a challenging aerobic tempo would be a 6, lactate threshold work occurs at about 7 to 8, climbing and time trial efforts are a solid 8 (sometimes 9), and VO2 intervals and all-out sprints are the only efforts that reach 10.
Just as the Borg Scale multiplies the perceived exertion number by 10 to correlate with heart rate, the number chosen on the 1 to 10 scale, multiplied by 10, seems to correlate closely to the percentage of VO2 max that an athlete is currently maintaining.
RPE and the Talk Test
The Talk Test is another simple way for athletes to use RPE during exercise. As intensity increases and breathing rate increases, athletes struggle to say words and sentences before needing to take a breath. An easy pace is often called a “conversational pace” because you can comfortably engage in full conversations. When your breathing goes from deep and labored to uncontrollable panting, that’s a sign you’re above your lactate threshold intensity. The talk test is also a way to tell how hard a competitor or training partner is going. Listening to their breathing, or trying to engage them in conversation, can indicate how close they are to their limit.
10-point RPE Scale (Perceived Exertion)
|When you say…||It means you’re at…||And you can…|
|0-1||Little to no effort||Talk freely, breathe through your nose|
|2-4||Active recovery pace||Talk comfortably|
|4-5||Aerobic “cruising” pace||Talk comfortably, breathing through mouth|
|6||Aerobic “tempo” pace||Talk in shorter sentences while breathing somewhat hard|
|7-8||Challenging lactate threshold pace||Talk only in short phrases due to labored, deep breathing|
|8-9||Time trial and/or hard climbing pace||Utter a word here or there between panting breaths.|
|10||Maximum effort (short sprints or 2-5 minute all-out VO2 max intervals)||Grunt. Groan. Cry.|
Using Perceived Exertion in Training and Racing
Rating of perceived exertion is useful during any type of exercise, and is often the best metric to use during competition.
Using RPE with Power, Heart Rate, and Pace
Power meters provide cyclists with accurate and direct measure of workload. Runners, triathletes, and cyclists can use heart rate monitors, continuous glucose monitors, and wearable trackers for sleep, recovery, hydration, blood glucose levels, and more. As a result, some athletes are tempted to relegate RPE to the trash bin of sports science history. Not so fast.
Cycling power meters make RPE more important than ever. While it’s true that 200 watts today is the same workload as 200 watts tomorrow, RPE provides valuable context to power files. When you’re fresh, 200 watts may feel like a moderate spin. When you’re fatigued you may feel like you’re working harder than normal. Athletes use terms like ‘sluggish’, ‘heavy legs’, ‘pedaling through peanut butter’ to describe those same 200-watt efforts.
Similarly, RPE provides context to heart rate and pace information. An 8-minute-mile pace may feel sustainable one day, but as hard as race pace another.
RPE is a great early warning device for revealing fatigue; your body is telling you it can still do the job, but that even though the work being done is the same, the effort to complete it is greater.
RPE and Recovery Monitors
RPE can even provide context to recovery monitor data. If your Whoop, Oura, or Garmin says you are recovered and ready to train or race, check in with your RPE to see how you’re really responding to intense efforts.
Measuring Training Progress with Perceived Exertion
RPE can indicate progress, even without a change in your power output or pace. For example, at the beginning of the season, a 20-minute climb at 250 watts average power may feel strenuous enough to rate a 7 or even an 8. Later in the season when your fitness has improved, riding at 250 watts up the same climb may take less out of you and feel more like a 6. An RPE of 7 to 8 on the climb may end up being 275 watts at the height of the season.
Racing by Feel: RPE in Competition
We include RPE values with each workout in our library, and athletes should record subjective information in training logs. Not only is perceived exertion important for providing context for power and heart rate files, but it also helps athletes learn to accurately evaluate intensity level in the absence of all other technologies.
During races, RPE is often the most accurate and realistic way to gauge intensity. For instance, we know power output starts to decrease at altitudes around 5,000-6,000 feet above sea level. Core temperature, fatigue, caffeine, and stress affect heart rate response to exercise. So, what should your target power output or heart rate be on a climb in a cold rainstorm at 10,000 feet above sea level, six hours into the Leadville 100 mountain bike race? There’s no formula for that, and no field on your GPS watch or head unit that can tell you what to do. But you still know what an RPE of 7 out of 10 feels like.
One of the biggest goals we have when working with athletes is to teach them to train and race by feel. Often, an athlete’s best-ever performances happen when they tune into their bodies instead of watching the numbers. Keep recording the data so you can look at it later, and so we have it for your long-term training history. But in the moment, you want to be able to nail power, power, and heart rate values without even looking at a display.
The mark of a skilled athlete is learning to use technology effectively while also reducing your dependence on it.