Rate of Perceived Exertion

When I first began working out, I didn't know how exercise was "supposed" to feel. At first, I thought that the harder I was breathing, the more effective my exercise would be. After a few years of reading, talking to mentors in the fitness industry, and practicing, I've become more in-tune to my body. However, for beginners and pros alike, the Borg Scale of Perceived Exertion can be a powerful resource for improving fitness and predicting blood sugar changes.

In the 1950's, Dr. Gunnar Borg introduced the Borg Rating of Perceived Exertion Scale, now commonly known as RPE. RPE assesses exercise intensity in a holistic way, based on heart rate, breathing rate, sweating, and muscle fatigue. (Borg, Gunnar. Borg's Perceived Exertion and Pain Scales. Champaign, IL: Human Kinetics, 1998. Human Kinetics. Web. 23 Aug. 2009. )

(Barder, Owen. "Heart Rate Zones." Running For Fitness. Web. 23 Aug. 2009.)

You should determine your level based on your heart rate, breathing rate, sweating, and muscle fatigue. Of course, if you feel at any point that something hurts like it shouldn't--even if you're not breathing hard or sweating--stop.

Although heart rate monitors are more exact, RPE is an easy-to-use, accessible tool for beginners and elite athletes alike. In addition, RPE takes into account if a person is tired, stressed, working out in hot weather, or training at a different altitude. Most importantly, RPE forces a person to listen to his or her own body, rather than relying on an external tool such as a heart rate monitor.

Because RPE is a subjective scale, a person determines his or her own perceived exertion. For example, a person who is out of shape feels may feel more exerted after walking a block than an elite athlete would feel. For this reason, one exercise routine isn't suitable for everyone. Two people with the same RPE may be running at a very different pace or lifting a very different weight.
     
How can RPE help you?

Exercise intensity, even within the aerobic and anaerobic zones, affects blood sugar in different ways. Anna wrote a great post about aerobic and anaerobic exercise and their respective influences on blood sugar; I hope that this article will give insight into how to apply RPE to these zones. Fitness professionals categorize exercise into four Zones, which are derived from the percent of maximum heart rate a person experiences while exercising. As we'll explore, RPE also correlates to these Zones.