How to Calculate Your Rate of Perceived Exertion

For the Strength Foundation 12-Week Workout program, you will work at 60 percent or more of your maximum heart rate. Your maximum heart rate is generally loosely calculated as the number 220 minus your age (for example, if you are 50 years old, your max heart rate would be 170); you can also have an evaluation by a physician to determine your max more accurately.

To measure your heart rate, you can buy a heart rate monitor and use a chart like the one at the American Heart Association to keep track of it. However, by using a monitor and chart to track your heart rate, you are relying on potentially arbitrary numbers, which are immune to changes in your fitness level.

Instead, Wicks recommends you use your Rate of Perceived Exertion (RPE). Your RPE will be how hard, on a scale of 1 to 10, you perceive yourself to be working. As you get fitter, a higher heart rate will feel easier, but if you are relying on your RPE, you will continue to push yourself up to your new, higher target range. “Basing a workout on your RPE means you’re basing it, not on arbitrary values that are given to you, but on what you are putting into it,” says Wicks. It’s a method that adapts with you.

To measure your RPE, concentrate on how much talking you could do at your current rate of exertion. Below, a handy table to guide you:

Talk Test RPE Scale Heart Rate (% Max)
The weather, politics, books; you could talk about anything, with ease. 2 - 3 40 - 50%
Breathing slightly labored; you can still talk, but you have to focus. 4 - 5 50 - 60%
Breathing challenging, but doable. Talking is more effort, and you’d just as soon not. 6 - 7 60 - 75%
Breathing hard; conversation nearly impossible. 8 - 9 75 - 90%
Can’t talk without gasping for air. You can’t sustain this level of intensity for more than a few seconds—nor should you. 10 90%