In the course of your training you have probably heard about your target heart rate, and how, if you stay
within this rate, the gates of fat-burning heaven will open and you will automatically be whisked away to a
You have probably seen those funny little â€œTarget Heart Rateâ€� charts, or â€œYour Fat Burning Zoneâ
€� chart or something similar to these that tells you where you should be in order to get the most out of your
training. You have also probably seen very expensive heart rate monitors available that you can wear on your
wrist, waist or chest that tell you exactly what your heart rate is so that you can attempt to keep it there.
Well, I want to tell you today that aside from a few circumstances when those devices might prove useful, they
are a total waste of time, money and energy for healthy individuals that can train as hard as they can stand.
Your Target Heart Rate
The "Target Heart Rate" is the level at which it is recommended you should be working in order to challenge
the cardiorespiratory system and be working in the "training" or "aerobic" zone. What does this mean in
English? Simply stated, it means the lowest possible heart rate that will improve cardiorespiratory fitness.
Therein lies the problem with these formulas.
The most prominent and accurate means of determining your target heart rate is the Karvonen formula. This
formula calculates a percentage of the heart rate reserve, which is the difference between the resting heart
rate and the maximal rate.
Heart rate reserve = maximal heart rate - resting heart rate
Maximal Heart rate is the highest rate a person can attain during exercise. While an electrocardiogram test
would provide the most accurate MHR, for practical application an age-predicted heart rate formula was
Maximal heart rate = 220 - age
This formula is based on the assumption that one's Maximum heart rate at birth is 220 and decreases by one
every year. The accuracy of determining maximal heart rate based on this formula can vary at any given age
by +/- 10 beats per minute but it provides a quick and easy way of determining this value without complex
tests or mathematics.
Resting Heart rate is the rate at which your heart beats at rest. It is recommended that this rate be taken
immediately upon waking, counting the pulse for a full 60 seconds, 3 mornings in a row and averaging the
Determining The Target Heart Rate Ranges
Using the Karvonen formula, the generally accepted heart rate ranges are between 60% to 80% of the
maximal heart rate reserve.
So, your Target heart rate = % intensity X heart rate reserve + resting heart rate
Here's how it would be calculated for a 45 year old with a resting heart rate of 80 and an age predicted
maximal heart rate of 175 at an 80% intensity level of maximum heart rate reserve:
175 (age predicted MHR)
- 80 (resting heart-rate)
= 95 (heart rate reserve)
X .80 (intensity level)
+ 80.00 (resting heart-rate)
= 156.00 (target heart rate for 80% exertion)
It was recommended that the formula be applied to both ends of the range, 60% and 80%, to determine the
target heart rate training zone.
To allow people easy reference for their intensity levels, Target Heart Rate Charts are generally posted in
gyms and especially in the cardio rooms of gyms. See the Heart Rate Chart for an example.
I donâ€™t know about you, but that was more work than I am willing to do to determine how hard I should
be exercising! Even looking at the chart can be confusing as well as misleading for someone who is healthy
Lose Fat, and Get In Shape WITHOUT Charts and Numbers!
I have to admit that for certain people knowing what your heart rate is can be invaluable information. For
instance someone with heart problems, or someone that is recovering from heart surgery usually has specific
guidelines set up by their doctor as to how much stress they can put on their heart. Also, certain athletes like
marathon runners, often measure their heart rate as part of their training to better pace themselves for a race.
Aside from these and others specific needs, for most of us, knowing your heart rate is useless information, and
information that can often lead to undertraining. Yes, thatâ€™s right UNDERTRAINING. More on that later.
First off, I wanted to go over the fact that you will not burn more fat training in one zone vs. another. Yes, I
know, â€œthey sayâ€� that training in such-and-such a zone you will burn a higher percentage of fat as fuel.
What â€œtheyâ€� donâ€™t tell you is that once you are done with that training, and you eat, you will
replenish what was lost during that workout, and if the calorie deficit was not enough, whether it was in a
specific training zone or not, you will not lose weight regardless.
The following was taken from â€œA Practical Approach to Strength Trainingâ€� by Matt Brzycki and
explains in detail what I am getting at:
â€œA greater percentage of carbohydrates are used as an energy source during exercise of higher intensity.
Conversely, a greater percentage of fats are used as an energy source during exercise of lower intensityâ€¦
These physiological facts have led to the mistaken belief that the â€œfat-burningâ€� (or low intensity)
exercise is better than â€œcarbohydrate-burningâ€� (or high intensity) exercise when it comes to losing
weight, â€œburningâ€� fat and expending caloriesâ€¦
â€¦ In truth, even though the percentage of calories used from fats are greater during low intensity exercise,
the total number of calories expended during high intensity exercise is greater (Bryant, Peterson and Hagen
â€¦ Based upon the ACSM formulas for determining oxygen uptake and caloric expenditure during walking
and running, a 165-pound man who walks 3 miles in 60 min. will utilize roughly 4.33 cal./min. Over the
course of his 60-minute walk, his total caloric usage would be about 260 calories. If that same individual ran
those 3 miles in 30 minutes, he would use about 13.38 cal./min. In this case, he would have expended about
401 total calories during his 30-minute run. So exercising at a higher level of intensity used up significantly
more calories than exercising at a lower level of intensity (401 calories to 260). This is true despite the fact
that the activity of the lower intensity was performed for twice as long as the activity of the higher intensityâ€¦
â€¦ The calculations have been corroborated by research in the laboratoryâ€¦ The intent behind advocating
low intensity exercise of long duration is to enhance safety and improve compliance in the nonathletic
population. However, low intensity exercise is not more effective for fat loss than high intensity exercise
(Bryant, Peterson and Hagen 1994; Porcari 1994). In order to lose weight, more calories must be expended
than consumed to produce a â€œnegative calorie balanceâ€� or calorie deficit. Whether carbohydrates or fats
are used to produce this negative balance is immaterial. A caloric deficit created by the selective use of fat as
and energy source doesnâ€™t necessarily translate into greater fat loss compared to an equal calorie deficit
created by the use of carbohydrates as an energy sourceâ€¦ Finally, it should also be noted that low intensity
exercise usually doesnâ€™t elevate the heart rate enough in healthy adults to produce an aerobic conditioning
So what is my point with all of this? Quite simply, paying attention to the heart rate charts and trying to stick
within a â€œfat burning zoneâ€� is illogical, and counterproductive. You will lose more fat training at a
higher intensity for a shorter period of time, and that is a known fact and as simple as it gets. Yes, it might be
more uncomfortable to do this, you will sweat more, expend more energy, feel more tired afterwards, etc., but
in the long run, it will do more for you.
My second point ties in nicely to this last point. Namely, if you try and stay in these predetermined zones, you
are cutting yourself short, and potentially UNDERTRAINING yourself. You will not only lose more fat by
training at a higher intensity, but you will also get your heart in better shape as well which will lead to better
training in the weight room and ultimately, lead to better results overall.
We are all masters of our own destiny. We know if we are training as hard as we can. When you are on that
cardio machine, ask yourself: Is this as hard as I can make this? Can I raise the level any more? Only you
know the real answers to these questions. Only you know if you are pushing yourself to the limit. Only you
know if you are going to leave the gym that day and feel victorious, or merely accomplished.
So, forget about those damn heart rate charts and start paying more attention to yourself and how you feel. If
you are a healthy individual with no medical concerns, then you should have no boundaries as to how hard
you can push yourself. If you were ever in sports do you remember training so hard, running so fast or
exerting yourself so much that you thought you were going to die? Did you? Exactly. You not only didnâ€™t
die, but you got in better shape because of that effort. That is the point that I am making.
I am not suggesting that you try and pass out every time to step into the gym, but there is no harm in pushing
yourself beyond what is comfortable, and in the process get in better shape physically, cardiovascularly, and
lose more fat than ever before. In order to do this though, you need to throw out all your preconceived notions
about fat burning, and all your trepidations about training beyond what is â€œcomfortableâ€�. No one ever
got a great body by training comfortably.
Keep up the good work,