In a previous post (Formulas Don’t Work), I bemoaned the continual use of “220-age” as the basis for CVT (Cardio Vascular Training).  In a first here at the Fanatics blog, I’ve invited the real expert to “splain” it to us – why this thing just doesn’t work.  You can also download the original white paper by Sally Edwards from her website, complete with detailed scientific references if you want to share it with others that need to know.  Here is the body of that paper:

The age-adjusted maximum heart rate formula (also known as the “age regression formula“) was developed a half century ago, at a time when the science of exercise physiology was in its infancy and the technological means to create a more accurate exercise prescription or testing protocol was scarce. The result was that the “220 Minus Age” formula was neither created nor validated based on supported research or clinical testing1. Today, the health and fitness industry continued support of an archaic, unproven formula is (a) potentially hazardous to the public, (b) a severe blow to our effectiveness and credibility, and (c) a tragic undermining of the proven advances and discoveries in exercise physiology over the last half century.

Here ten reasons why “220 Minus Age” gets a failing grade:

1. The formula’s inventor acknowledges its unscientific development.
The equation was created in the early 1970’s by scientists Fox, Naughton, and Haskell who intended it to be a rough formulation and not meant to be representative of the entire population. All subject in the studies referenced were under 55 years of age and male. Although the equation has become accepted and the standard in the literature and is used widely in clinical and fitness settings, its validity is uncertain.

2. There is no scientific research to support it.
There is no scientific validation of this formula. There is simply no research to support it.

3. It is physiologically nonsensical.
There is no physiological reason why everyone of the same age should have the same maximum number of heartbeats in a minute’s time. In fact, we KNOW this isn’t true. For example, as fit individuals age, their maximum heart rate drops very little.4 Research has shown that the maximum heart rate of individuals of the same age can vary by 11 bpm based on many variables especially sport activity.5 Yet this formula claims to scientifically prescribe intensity-based training levels for individuals, even as it ignores their scientifically established individuality.

4. It is useless.
There is a common assumption that any of the equations that predict your individual maximum heart rate will be both reasonably accurate and reasonably useful. Such is not the case with “220 Minus Age.” Intended to guide users to exercise in the right cardiovascular training zones (CVT), in fact, the formula doesn’t accomplish this. “The 220-age formula designed to predict maximum heart rate is useless” according to Carl Foster, Ph.D. and past president of the American College of Sports Medicine, “because it simply is not accurate.”

5. It is elitist.
Don’t believe Dr. Foster? Well, how about trying to convince pro athletes that they should go back to using “220 Minus Age,” if they ever did. Why do we think that pro athletes somehow deserve more accurate training regimens than fitness exercisers? There is value to increased precision, especially for those seeking weight loss or true aerobic benefits from their physical activity.

6. It may be dangerous.
The formula is built into and displayed on the consoles of most pieces of cardio-equipment. But, if followed, it can be dangerous overestimating maximum heart rate in young adults and underestimating it in older people. Using 220-age forces finess enthusiasts, with the air of scientific authority, to exercise at too high or too low a cardiovascular intensity. Similarly, the formula also leads some individuals to exercise at intensities too low to achieve needed health benefits. As finess professionals, we need to ask ourselves if we could be at legal (not to mention ethical) risk for using an equation to prescribe exercise intensity which we have ample reason to suspect is inaccurate.

7. It is an embarrassment.
Savvy consumers can prove for themselves that their Max HR isn’t what the formula says it is, so how much credibility do you think they give training professionals who say otherwise? Yet working this formula is a requirement to pass most personal trainer certification tests. And, worse still, the formula is posted in most health clubs.

8. It allows us to be lazy.
In the early 1990s, I created the original five heart rate training zones, each built on 10% of your maximum heart rate. Those zones were first published in my work, The Heart Rate Monitor Book, and have subsequently been adopted as the standard CVT zones programmed into millions of cardio machines. I acknowledge that at that time, almost twenty years ago, I, too, was unwilling to change and to recommend alternative methods for prescribing CVT zones. Accepted by the ACSM, this mythical formula was just too easy, and it was even then a dogma. I have subsequently confessed my error in recommending the formula and apologized for supporting such a simplistic means of determining such an important value.

9. There are scientifically validated alternatives that are safe and effective.
To the best of my knowledge, at this time there is no equation that has been proven accurate enough in predicting maximum heart rate. None whatsoever. This does not mean that we don’t have any proven means of achieving the same end, because we do.

Sub-maximum testing protocols, or “sub-max tests,” are a straightforward method of estimating maximum heart rate, based on a physiological response to a safe level of exercise stress. One such test, “The Can-You-Speak-Comfortably Foster Test” is scientifically validated by Carl Foster, Ph.D. There are others.
And, yes, I have a business that promotes these alternative tests and protocols, yet I’m sure there are many other means of setting CVT levels that I haven’t even heard of and from which we would all benefit.

10. We have a responsibility to do our best.
Because the estimation of maximum heart rate comes from a professionally supported mathematical formula, it carries an air of scientific authority. If we health and fitness professionals want to continue to be seen as authorities, we need to do our best for our clients, whether it’s easy for us or not. Supporting the use of this outdated formula is simply not the best we can do.

Sally Edwards, MA, MBA
CEO, Heart Zones USA
Applied Exercise Scientist
Author of 22 books on health, training, performance, and fitness
Professional triathlete and runner
sally.edwards@heartzones.com

Heart Zones USA, The Training, Education, Coaching, and Club Programming Company
2636 Fulton Avenue, Suite #100
Sacramento, CA 95821 USA

November 20, 2009