On a scale of one to 10, how hard do you push yourself during your workouts? That's RPE in a nutshell. A rating of one might be lying in corpse pose during yoga, while 10 is more like you being chased by zombies in your dreams after that Walking Dead marathon. Since it's all based on your own perception of how hard you’re working, RPE helps you decide when you need to push harder to see the results you want. (Want to try fun experiment? See how hardcore (or not) you are by ranking your RPE and then correlating it with the BPM readout on your HRM!).