What Does RPE Mean? Rate of Perceived Exertion Explained Simply

Rate of perceived exertion (RPE) is exactly what it sounds like: a rating of how hard an effort feels to you, from the inside. Not how much weight is on the bar, not your heart rate on a screen, but the whole felt sense of the work: your breathing, your muscles, how much is left before you have to stop.

The idea came from the Swedish researcher Gunnar Borg in the 1960s. He wanted a single number that captured effort, and found that a trained person's rating tracks their physiology well enough to be genuinely useful. That is the surprising part. A feeling, scored on a fixed scale, behaves like a measurement.

There are two main versions, and they can look confusing side by side because the numbers do not match. Pick one and stay with it.

The Borg 6 to 20 scale

The original scale runs from 6 to 20, not 0 to 10. That looks odd until you learn the reason: Borg lined it up with heart rate. Multiply your rating by ten and you get a rough heart rate, so a 6 maps to about 60 beats per minute at rest and a 20 maps to around 200 at maximum effort. It is common in cardiac rehab and research.

The 0 to 10 scale

Borg later built a simpler 0 to 10 version, and this is the one most gyms, coaches, and apps use today. Zero is sitting still, 10 is the hardest effort you can imagine. It is easier to hold in your head, which is most of why it won.

For lifting, the most useful way to read RPE is as reps in reserve, sometimes shortened to reps left. You subtract your rating from 10 to get the number of reps you could still have done with good form.

• An RPE of 10 means you could not have done another rep. Zero in reserve.
• An RPE of 8 means you stopped with about 2 reps still in you.
• An RPE of 6 means you had roughly 4 reps left, which is fairly easy for a working set.

This matters because most strength and muscle gain comes from sets taken close to failure, but not always to it. Training everything to a flat 10 every session piles up fatigue fast. Prescribing sets at RPE 7 to 9 keeps the effort high where it counts while leaving something in the tank for the next session.

This is the fair objection. It is a self-report. Can it be trusted? The evidence says: more than you would guess.

A 2022 systematic review and meta-analysis pooled RPE studies during resistance exercise and found the ratings lined up with objective measures of exertion with a weighted correlation of about 0.88, which is a very strong relationship. In plain terms, when people say a set felt like an 8, the physiology tends to agree. Reviews of cardio training find much the same.

The catch is that RPE is a skill. Beginners often underrate hard sets because they have never met their true limit, so they call an RPE 9 a 7. It sharpens quickly with practice, especially once you have taken a few sets genuinely close to failure and learned what that feels like.

1. Pick one scale. The 0 to 10 scale is the easiest to live with. Ignore the 6 to 20 version unless a program you follow uses it.
2. Rate the last rep, not the average. Ask yourself how many more clean reps you had at the end of the set. That number, subtracted from 10, is your RPE.
3. Aim most working sets at RPE 7 to 9. Hard enough to drive progress, with a rep or two spare so you can train again soon.
4. Write it down. Log the weight, reps, and RPE together. Over a few weeks the same weight feeling easier is progress you can see.
5. Save RPE 10 for rare tests. A true maximum effort is a measuring tool, not a daily habit.