Heart Rate Training Zones: A Convenient Method to Maximize the Effectiveness and Results of Exercise Routines

Here’s an article from Dr. Fuhrman's colleague Dr. Steven Acocella, MS, D.C., DACBN, Board Certified Clinical Nutritionist, American College of Lifestyle Physicians, and a Diplomat of the American Clinical Board of Nutrition:

In disease free individuals resting pulse rates reflect our current state of fitness. Being aware of our pulse rate can help us avoid injury when beginning an exercise regime, measure the effectiveness of various exercise routines and determine if we are under or over training. By monitoring our heart rate throughout an exercise session we can adjust our efforts in real time so that we achieve our desired results and goals. Using our heart rate as a guide we can specifically focus on improving cardiovascular health, maximizing body fat reduction, improving stamina and endurance or build lean-muscle mass. As we become more fit, plotting our resting heart rate over a period of time on a graph will demonstrate our progress as clearly as fitting into those skinny jeans again!

Heart rate training is based upon a key anchor point, our maximum heart rate (MHR). From our MHR we derive heart rate training zones. As we will see later, these zones help us target the results we want and achieve those goals from our efforts. There are 3 ways to determine what our individual MHR is, a strictly mathematical formula based on age or by measuring our heart rate during actual exercise. There are 2 methods that use our ‘perceived level of exertion’ (how we feel) during actual exercise. I prefer these exertion-based methods of capturing MHR as they better reflect individual fitness level and ability. However, a resent study reviewed some 50 different mathematical MHR formulas and identified the most reliable and accurate calculation method. The study found that the maximum heart rates obtained using this formula varied only fractionally when compared to exercise derived MHR’s in the same subjects. Certainly, for the average fitness enthusiast, both methods are useful and valid. I will present the mathematical and exercise derived methods in this article.

There are two ways to obtain your pulse, manually by feel or by using a heart rate monitor. Heart rate monitors use a transmitter housed in a chest strap worn during exercise; this device detects the heart’s electrical activity and then send this information to a receiver, usually housed in a wrist watch which displays heart rate and other data. Once only available to professional athletes, personal heart rate monitors are quite inexpensive and accessible to most of us weekend warriors. If you shop for a monitor I recommend you find one with a built in “Fit Test”, a program to calculate your heart rate zones via a guided exercise routine. Many home and most club gym exercise machines have heart rate monitor receivers built right into them. If you have access to these machines you may only need to purchase the chest strap. Some machines with built-in receivers even adjust the workout intensity automatically based upon the user’s target heart rate zones!

If you don’t have a monitor here are a few tips on taking your pulse directly. You can take your pulse on the underside of your wrist on the thumb side using your 1st and 2nd fingers (never use your thumb to take a pulse). Or, some prefer to take the carotid pulse located on the front side of your neck about 1/3 of the way down and about an inch on either side of center. Practice locating your pulse. Once you’re good at finding and feeling the pulsing blood vessel, use a second hand watch and count the pulses for 60 seconds, this is your current heart rate. Once you’re proficient you can count the pulse for 30 seconds and simply double the number. Be sure to master pulse taking before you need to do it during a heart rate test or when exercising.

Firstly, let’s determine your MHR mathematically. Simply plug your age into this equation: MHR = 205.8 – (0.685 x AGE)

For example, the MHR for a 45 year old is: MHR = 205.8 – (0.685 x 45) = 175 Beats per Minute

Now let’s look at the methods that use exercise to capture MHR. The first method, known as the Sub-Maximal HR Test is useful for people that are just beginning an exercise program, recovering from an injury, medical procedure or anyone not in good enough shape to push themselves to their absolute limit. This method instead derives MHR by estimating or extrapolating from a heart rate obtained from a less than all out effort. This test is most accurate when supervised by a professional but an average test is still quite useful.

Using walking as the ‘control effort’ - map out a 1 mile course, a ¼ mile track is optimal but not mandatory. Walk briskly (without jogging) pushing yourself into a challenging but comfortable stride. A good rule of thumb is the talk test, i.e., you should be able to maintain a conversation during this level of effort. At about the ¾ mile mark, without stopping, take your pulse. Keep walking and repeat taking your pulse a couple more times during the last quarter mile. If there is more than a few beats difference in each heart rate simply add them together and take the average to obtain a more accurate number. If you are using a heart rate monitor simply note your HR 3 times during the last ¼ mike and take that average. Now that you have your sub-maximal heart rate, add 50 beats per minute (BPM) to that number to calculate your MHR. Again, this is a working ball-park average but it’s still very useful especially for those of us closing the doughnut box and getting off the couch for the first time.

Finally, we’ll look at obtaining a MHR from the Maximal Effort Method. This method should be utilized only by those whom are already fit and in good cardiovascular health. Be forewarned that this method is quite challenging. Choose an activity such as biking, an elliptical machine, treadmill or any aerobic activity in which your body position is upright. I do not recommend recumbent exercises or swimming for the Maximal HR Test as MHR can be sport specific and these activities have the greatest variation.

The Maximal Effort Method test is designed to last about 15 minutes. Begin to exercise and after about a 3 minute warm-up begin to exercise at the level of effort described for the sub-maximal test. Maintain this level for a full 10 minutes. Once you are at this 10 minute mark the fun begins. Over about a minute, accelerate and intensify your effort until you can push no more. You should be at a level of effort that is very uncomfortable and barely sustainable. After pushing yourself at this highly competitive pace for about a minute note the reading on your heart rate monitor or take your pulse (ask a partner to help you by tracking the time for you) while maintaining your pace. It is this pulse rate during this final minute that is your MHR. Once you have obtained it you can then slow down, cool down and then fall down!

So, now that you have obtained your MHR from the mathematical or effort derived methods we’ll apply this information to get results from our workouts. The broadest application is to define a single target heart rate range to make sure you are getting something out of your workouts. This is a general heart rate range that is required to improve respiratory capacity, cardiovascular health and general overall fitness. This HR range is 60 – 85 percent of our MHR. To find your range simply calculate these 2 numbers:
  • Lower limit of Heart Rate Range = MHR X .60
  • Upper Limit of Heart Rate Range = MHR X .85
So, our 45 year old with a MHR of 175 BPM would have a beneficial heart rate training range of 105 BPM – 149 BPM (175 X .60 and 175 X .85).

Here’s where monitoring your heart rate during exercise begins to become useful. As we become more fit, activities that initially brought our heart rate into a beneficial range become too easy. But many of us continue our routines and hence our efforts become less productive as they no longer stress our bodies to the point of gaining improved fitness; this ‘staleness’ is avoided by heart rate guided training. We can engage the same activities but are forced to work harder to bring our heart rate into this beneficial zone. But this is only one application. MHR can be tailored for much more specific training goals.

By breaking this wide training range into more narrow ‘zones’ we can use heart rate data to customize our workout intensities for optimal and specific results. Generally, I use 4 reference zones. All are expressed as a percentage of MHR with an upper and lower limit. Although there are overlapping benefits, generally speaking each zone has a particular result associated with it. The percentages of MHR for each zone are:
  • Zone I – Light Intensity 60 -70 percent of MHR
  • Zone II – Moderate Intensity 70 -80 percent of MHR
  • Zone III – Heavy Intensity 80 -90 percent of MHR
  • Zone IV – Maximum Intensity > 90 percent of MHR
So, again using our 45 year old as an example our target heart rates would be:
  • ZI = 105-122 BPM
  • ZII = 123-139 BPM
  • ZIII = 140-157 BPM
  • ZIV = 158-175 BPM
Here’s an overview for each zone:

Zone I – This is the easiest level of intensity you can work at and still gain benefit. It’s best used for overall health, flexibility and agility and maintaining a weight reduction. This is an excellent zone to stay within during the first 1 -3 months of beginning an exercise plan to avoid injury, especially for those who have not engaged in a fitness program for a long time. It’s also the warm-up and cool down zone to enter into or come out of more intense exercise.

Exercise at this level should feel easy and pass the ‘talk test’. You should never be out of breath, feel any pain or burning and be able to maintain this effort indefinitely.

Zone II –Working out in this zone effectively builds endurance, stamina and muscle tone without significant increase in girth. It’s also excellent for cardiac strengthening and building co-lateral circulation (adding more small blood vessels in the extremities). This is an excellent zone to stay in during the first 2-4 months of training.

When in this zone breathing should be slightly labored but not difficult. You can still converse comfortably. You should not be in a ‘no-pain, no-gain’ condition but may need to vary your effort from time to time. When fit you should be able to maintain this level of effort for a few hours.

Zone III - This is the best zone to use stored fat for energy, i.e., the most efficient weight loss or ‘fat burn zone’. Zone III balances maximum caloric demand while still remaining under the anaerobic threshold, the key criteria for burning fat. In less fit people training in this zone too soon uses more glucose than fat for energy. As we become more fit and can maintain this level of intensity for longer periods of time it becomes fueled by an increasing percentage of energy from stored fat. This is why you often hear people say that they started working out and are “exercising like crazy but not losing any weight”. This is exactly why I recommend to patients that want to lose weight and are just starting out that they exercise in Zone II for a while. Pushing too far too soon can be counter-productive. It takes time for the chemical plant in our muscles to adapt to the new demands of exercise. The cells that use oxygen in producing energy increase over time (this is known as Davis’s Law) so that we can sustain a Zone III level effort for longer and longer. It’s the physiological equivalent to learning to walk before you can run, or perhaps this analogy can be applied literally!

Exercising in this zone should be quite challenging but still not painful. It’s the highest zone you can be in and still be able to carry on a conversation, albeit difficult and in-between breaths. You should be able to maintain this intensity for up to about 1 hour but that may be much shorter initially and increase proportional to you level of fitness.

Zone IV – This is the anaerobic zone whereby we use primarily glycogen (glucose stored in muscle tissue) for energy. This zone contributes greatly to the efficiency by which our muscles can burn fat in the lower zones. By pushing ourselves into this zone we raise our ‘lactate threshold’, the line between using fat verses sugar as a caloric energy source. The more time we can stay in zone IV the higher our lactate threshold and the longer and stronger we can perform athletically. This zone ‘ramps-up’ our muscles to burn fat while we’re at rest by making our ‘oven’ more efficient. Most importantly, this is the zone where the most dramatic muscle building gains live. We could call it the Buff-Zone!

Exercise in this zone can be maintained for only very short periods of time, usually seconds to a few minutes maximum. If you can maintain this zone for longer than 3 minutes you are either not in this anaerobic zone or your name is Lance Armstrong. You can not talk during this level of exertion and are in significant pain. There is no significant fat weight loss in this zone but rather a break down of muscle tissue that leads to growth. This is the ‘no-pain, no gain’ zone and if you’re in it you should be hating life.

Remember, as you become more and more fit the beneficial changes that take place are reflected in your heart rate. Make a chart and plot your resting pulse by taking it first thing in the morning before you get out of bed. Do this for a few months and you’ll see over time the line slopes lower and lower! As your resting pulse plummets the range of your resting heart rate and your MHR increases allowing your heart to work less hard at the same level of effort. By using your heart rate as a barometer of how hard you are exercising you will avoid boredom, progress plateaus and stagnation.

You are now armed with valuable and useful information about heart rate training. You can now see how knowing and using your heart rate can help you maximize weight loss goals, achieve those 6-pack abs and keep you moving onward and upward to the fittest you possible. I applaud you for taking the time to read this article, see you in the gym!
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Comments (3) Read through and enter the discussion with the form at the end
John Kenney - June 11, 2008 5:03 PM

I have recently committed myself to starting an excercise program. I am 43 yrs old and know that I have to make excercise a part of my life to maintain my health in my later years.
I came across Dr Acocellas article on
heart rate training zones. I was very impressed with the way Dr Acocella simplified what could have been a complicated article. Its good to know how to calculate my MHR properly as compared to 50 other mathematical formulas. I will use the information on the 4 zones as a guideline for my new excercise regimen. I had heart surgery years ago and Dr Acocellas information will help me ease into it slow and easy and progress as I get stronger.

Gail - June 12, 2008 8:12 AM

Thanks for this article Dr.Steve A. Your breakdown was very enlightening. I have never had it explained that way before, not even by my Cardiologist!

David Lena - December 27, 2009 12:43 PM

Thanks for very informative article. I used to train with a monitor many years ago. I'm now 42, max heart rate is about 195--down from 206 when I was 29 (need to purchase a new monitor). Current reading is off of my treadmill which takes a few seconds to lock-in. Anyway, I'm back into running and am looking to improve my fitness through interval work (if that's appropriate). I run about 25-35 miles / week over a hilly 6.5 mile loop. My question is: I'm usually in zone III for the 54-58 minutes it takes me on the course. How many Zone IV's would you suggest? From my experience, I don't think that I'd recover from more than one or two. I'd have to drop below zone III to rest enough to continue the workout. Anyway, thanks again. I'm getting a monitor today and get some hard data.

Dave Lena

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