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Track Your Training Intensity Using an Easy Scale

By Eric Heiden, M.D., Tribune Media Services, Source: Eric Heiden

Many exercise physiologists believe that the intensity of an activity is more important than how long you exercise or how many times you repeat an exercise.

But gauging exercise intensity can be difficult -- what's low intensity to one person can seem high to another. For that reason, scientists created a scale called the rate of perceived exertion (RPE). The RPE very accurately pinpoints exercise intensity for you personally. Each step on the RPE scale assigns a number to a sensation. When you perceive your level of exertion as weak, for example, that's a 2 on the scale. When you feel it's strong-- that's a 5. Maximum effort: 10. There are several scales of perceived exertion. We use the Borg scale that is scientifically validated. It looks like this:

Rating Description

0 -- Nothing at all

0.5 -- Very, very weak

1 -- Very weak

2 -- Weak

3 -- Moderate

4 -- Somewhat strong

5 -- Strong

6 -- Between strong and very strong

7 -- Very strong

8 -- Between very strong and very, very strong

9 -- Very, very strong

10 -- Maximal

(There is another Borg scale that rates effort between 4 and 20, but we have better results with the 0-10 version.) To get accustomed to using the RPE, try it out first under circumstances where you can pay close attention to your body's signals.

-- Choose an activity that's comfortable for you: walking outdoors, riding a bike, or walking on a treadmill.

-- Start at an easy pace.

-- Slowly increase the pace until you feel you are working at an intensity that is weak or easy -- one that doesn't require you to exert much effort to continue. This point or sensation is your RPE Level 2.

-- Now go a little faster, until you start feeling the effort is moderate. This is Level 3 for you.

-- Next, increase to an intensity that you feel is strong. This is Level 5.

-- Now increase your intensity until your pace is very strong -- between Levels 6 and 7.

You can now utilize this information to place your workouts at the intensity prescribed in any exercise program and in any activity -- the RPE is that accurate. When we test people in our lab using the RPE while simultaneously testing VO2max or blood lactate levels, we find that a person's RPE correlates closely with their metabolic response in 90 percent of cases. In other words, your body is good at telling you precisely how hard it's working on a chemical and metabolic level.

Many people prefer to gauge the intensity of their workout using a heart-rate monitor, but heart-rate monitors have their drawbacks. You need to calibrate your correct training zones to use one -- you can't depend upon the standard "220 minus age" formula. And you need to do so for each type of exercise you do, because your correct heart-rate zones for running will be different from those for swimming or for skating.

The RPE has none of these drawbacks. Thus, we prefer the RPE to assess and monitor exercise intensity -- for the 90 percent of people for which it works, that is. For 10 percent of people, however, the RPE does NOT work well. Namely, those who, during incremental tests in the lab, perceive their exertion as "2," then "2," then "2," then suddenly "10." Or those who might perceive the increases in their body's effort at the beginning but then jump from 3, say, all the way to 10.

If you want a precise RPE measurement, it's worth getting measured in a good lab, with expert supervision, so someone can simultaneously monitor your heart rate, blood lactate concentration and oxygen uptake while also doing your RPE. From the analysis of these numbers, the lab can then assess your individualized training zones.

(For more information on fitness from Eric Heiden, M.D., five-time Olympic gold medalist speed skater and now an orthopedic surgeon in Utah, see "Faster, Better, Stronger: Your Fitness Bible" (HarperCollins), which he co-authored with exercise performance physician Max Testa, M.D., and DeAnne Musolf. Visit www.fasterbetterstronger.com.)