Perceived exertion -- how hard you believe you are working your body -- may seem a subjective way to measure the intensity of your physical activity. However, studies show that the rate of perceived exertion (RPE) can provide a close approximation of your actual heart rate during exercise.

While some people use an RPE scale that ranges from 1 to 10, it is the scale ranging from 6 to 20 (see below) that can correlate roughly with heart rate. By multiplying your RPE by 10, you may approximate your heart rate. For example, an estimated RPE of 13 would correlate with an approximate rate of 130.


  • 6-7 = very, very light
  • 9-10 = very light
  • 11-12 = fairly light
  • 13-14 = somewhat hard
  • 15-16 = hard
  • 17-18 = very hard
  • 19-20 = very, very hard.
Important caveat: Your heart rate can vary considerably from the RPE-based estimate, depending on your fitness level, age and other variables, such as medication and caffeine intake