Exercise intensity can tell you if you’re working too hard or not. And your Rating of Perceived Exertion (RPE) is a common way to walk the fine line between overtraining and underperforming.
What Is Perceived Exertion?
Rate of perceived exertion (RPE) is the subjective measure of the intensity of physical activity, or more specifically, the intensity of exercise. RPE is a subjective measure of intensity and does not provide any information about how much energy is being expended for a given level of exertion. RPE is determined by the perception of an effort rated on a scale score.
The scale ranges from Level 0, which is no feeling of exertion at all, to Level 10, which is maximal exertion. Ratings between these two levels are made by estimating the number of points between them on the scale. This rating scale can be influenced by many factors such as how long you have been exercising, your fitness level, and your mood.
Some professionals in the field use RPE to prescribe and monitor strenuous exercise, but there are also people who argue that RPE should not be used to prescribe exercise intensity because it doesn’t provide any information about how much energy a person is expending or how many kilocalories are burned.
The Borg RPE Scale
The Gunnar Borg RPE Scale is a grading system for physical exertion. It ranges from 6 to 20, with 6 being very light and 20 being very heavy. Typically, a 6-10 on the scale indicates a moderate level of intensity while an 11-20 indicates a high activity intensity level
The Borg Scale was first used to measure the level of exertion in research regarding work capacity and aerobic exercise capacity. It has since then been used by a number of researchers who have found that the scale is valid and reliable.
It should be noted that the Borg Scale was not specifically designed to measure maximum effort in weight training. It’s been used by trainers and coaches for this purpose and it is posted on the walls at many gyms. However, the Borg Scale doesn’t actually work very well for this purpose.
Emerging training research on Heart rate and Exercise Intensity
According to a cross-sectional study of over 2,500 individuals divided into 4 groups based on their fitness level, Borg’s RPE is a good indicator of exercise intensity. Group 1 was sedentary, group 2 was moderately fit, group 3 was highly fit, and group 4 was elite athletes. Participants were tested on a treadmill or cycle ergometer.
Heart rate beats per minute, blood lactate, and Borg’s RPE were measured at the end of each workload. The researchers found a strong correlation between RPE and heart rate range and blood lactate.
They also found that the mean values for lactate threshold (LT) and individual anaerobic threshold (AT) corresponded to an RPE of 10.8 ± 1.8 and 13.6 ± 1.8, respectively.
Borg’s RPE seems to be an affordable, practical, and valid tool for monitoring and prescribing exercise intensity, independent of gender, age, exercise modality, physical activity level, and CAD status. And that exercising at an RPE of 11-13 (“moderate activity”) is recommended for less trained individuals, and an RPE of 13-15 (“vigorous activity”) may be recommended when more intense but still aerobic training is desired.
Meanwhile, another study has proposed a new scale measures RPE based on how many repetitions are left in a weightlifting set. The premise is based upon the assumption that the difference in the number of reps left before muscle fatigue is a good objective measure for how much work is left to be done.