Archive for maximum heart rate

Myth of Maximum Heart Rate

Question

What should my target heart rate be for safe exercise now that I’m reaching into my 60’s? or now that I’m ….?

Answer Part 1

There has been a consensus from people in medicine and in the various fields of exercise training that your maximum heart is determined by the following formula:

220 minus your age =’s Maximum Heart Rate

Then you take a percentage of that to arrive at your target heart rate for training.  Let’s first look at this formula stated above.

Background

This formula has been too casually utilized.  It has been promulgated as being scientific and over time has become the erroneous guideline for many in determining individual training levels.

It was founded in 1970 by Dr William Haskell.  There is a very good article in the New York Times that challenges this myth of maximum heart rate.  Below are excerpts from it:

The common formula was devised in 1970 by Dr. William Haskell, then a young physician in the federal Public Health Service and his mentor, Dr. Samuel Fox, who led the service’s program on heart disease. They were trying to determine how strenuously heart disease patients could exercise…

The subjects were never meant to be a representative sample of the population, said Dr. Haskell, who is now a professor of medicine at Stanford. Most were under 55 and some were smokers or had heart disease…

…At that point, Dr. Fox suggested a formula: maximum heart rate equals 220 minus age.

But the formula quickly entered the medical literature. Even though it was almost always presented as an average maximum rate, the absolute numbers took on an air of received wisdom in part, medical scientists said, because the time was right.

Answer Part 2

The American College of Cardiologists and the American College of Sports Medicine have come out with different guidelines.  I have seen that the American Heart Association used in the past the old formula.  I don’t know if they are still recommending this 220 minus age, equals your maximum heart rate.

Many have used the Karvonen Formula–See this link for an easy and quick calculation (and calculator)

Heart rate = ((Max HR-Resting HR)*%X/100)+Resting HR. (where %X =%MAX)

There is a great summary on a Wiki page here.  It provides more information than many would want.  It has other measurements and of course you can find the cited references.  Nice job.

So where does that leave us.

Answer Part 3

OK, whenever there are at least three answers proposed, be careful.  That means here, be careful!  I think that we don’t have a simple answer.  Also, we just don’t really know.  So in light of doing a treadmill test or similar at a human performance testing laboratory–what do we do?

We could use our common sense (or uncommon sense, as the case may be).  Take measure of who is asking.  What kind of condition are they in, any medical concerns–use a doctor to rule out medical problems.  What is their exercise history both recent and past composed of. Etc.

I personally like the Karvonen Formula or one of the other similar ones (they seem to differ in the range of standard deviations allowed).  In addition, I also like the Scale of Perceived Exertion.  This scale has shown good reliability with different groups of people–but it has doubt for some populations (caveat emptor).  Many people have derived their own modified Borg Scale.  Different groups have assigned different numbers meaning different levels of exertion.  (here and here for example)  Most importantly find your own subjective report that you can use consistently to gauge your work effort.  Be smart and be aware always.  Don’t use scales of any kind without retesting.

This retesting is important.  By retesting I mean how do you feel after exercising at your level of exertion.  How long does it take for you to recover–both in immediate heart rate (and breathing rate) and in the following days.  How you are sleeping and waking are always good barometers to pay attention to in determining how stressed you have become or not.  Also consider your mood swings and general level of energy.  This evaluation is always seen in our relationships with both are family/friends and in difficult situations especially.

Summary

Training is never done in isolation to how ones heart rate only is responding.  One needs to pay attention.  This attention would benefit by having a check list (hmmm another article someday)

Hopefully some of you will read this article and add what you have found to be important in determining your level of work.  Add your comments below.

Good training–may our hearts expand and receive the benefits of training beyond the base physiological parameters of regular exercise prescription.