If you do much exercising, you’ve probably heard of the rating of perceived exertion (RPE). It’s a way to pick a number to equal how hard you feel you are working. Sometimes the scale goes from zero to 10. Another scale goes from six to 20. The lower numbers are for a light workout, and the higher numbers are for harder workouts.
Physical therapists in England studied back pain patients using RPE while exercising in a pool. They found at low workloads (not enough to be aerobic), the RPE wasn’t a very good measure of intensity. Once the patients got their heart rates up to at least 55 percent of their maximum, RPE was accurate. Used this way, it predicts a safe exercise intensity.
This is important because back pain can lead to reduced activity. Then the patient gets deconditioned and weak. The heart and lungs don’t work as well. Pool therapy can help improve this while also reducing back pain. Since everyone has a different response in the water, some way to self-regulate intensity is needed. The authors of this study suggest using the RPE Scale for those patients in a pool program who are able to get their heart rate up high enough.