Science Examines the Relationship Between Rest Periods and Rate of Perceived Exertion

Rate of perceived exertion, or RPE, is a good tool for measuring effort during a workout. New studies suggest it actually has more to do with rest periods than sets or reps.

I always say that consistency is the king of exercise results. Getting out there and doing something, anything, on a regular basis is better than sometimes doing the “best” exercise. If you just go and give it your all, you’ll get good results.

If I’m right, then rate of perceived exertion (RPE) might be a more important scale than people give it credit for. If something feels too hard then you are less likely to want to do it. Running is a perfect example. I can’t tell you how many times people have told me they hated running and thought it wasn’t for them for no other reason than they were simply running too fast. Slow it down, enjoy the run, and voila! Using RPE, you will actually get amazing results because you’re spending more time doing the work than dreading the work.

Researchers recently performed a study for the Journal of Strength and Conditioning to find out how RPE works in regards to weight training. Specifically, the researchers wanted to see how the rate of work affects RPE. This is different from load, of course, since a heavier weight will yield a higher RPE for any given amount of exercise. As such the researchers picked one weight for each participant, which was 60% of their one rep max.

The researchers measured three protocols. One was 3 sets of 8 reps with a 3 minute rest. The second protocol was 3 sets of 8 with a 1.5 min rest, and the third was 2 sets of 12 with a 3 minute rest. RPE was lowest for the first protocol and increased from there. Interestingly, there was a closer relationship between the last two protocols, which suggests that work rate is a more important factor than how many reps per set you do.

In other words, the more work you do in a given time impacts your perceived effort more than how much work you do in any given set. These results suggest that manipulating rest periods plays a bigger role in a resistance workout than any other factor. The benefits of this study should be clear.

Remember, if your RPE for any exercise protocol is too high, you simply won’t do it. And if it’s too low it won’t be any fun at all. You want to hit just the right zone. What the study can’t tell you, however, is which protocol to choose. Sure, some protocols may yield consistently higher or lower RPEs, but everyone’s RPE scale works a little differently. Although one protocol might yield a higher RPE for everyone else, for you it might be too high to be enjoyable, and for someone else that might be the RPE sweet spot.

Ultimately we would all benefit from being honest with ourselves and judging our preferences without prejudice. Since consistency is more important than the activity you’re doing, taking the time to find your ideal RPE zone for each exercise you do could yield years of superior benefits.


1. Justin A Kraft, et. al., “Session RPE Responses during Resistance Training Bouts Equated for Total Work but Differing in Work Rate,” Journal of Strength and Conditioning DOI: 10.1519/JSC.0b013e31829b569c

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