I’ve been doing MAF style training during the winter months for the last few years now, but I’m beginning to think that although the concept is a good one, that the actual MAF method doesn’t work for me. With that in mind it was time to put my thoughts into a blog post.

What is MAF Zone Training?

MAF or Maximum Aerobic Function training is a concept developed by Dr. Phil Maffetone.  The basic premise is that everyone has an exercise intensity that equates to their Maximum Aerobic Function and training at this intensity allows them to develop and improve their efficiency at this intensity without too much stress on the body and it’s various systems. In essence, training at or around your MAF heart rate allows you to become more efficient at that heart rate and so end up faster without too much stress.

The Aims of MAF Zone Training

Using this concept, Dr. Phil Maffetone has you training at your MAF Heart Rate for a large percentage of all your training. His training regimeis a holistic programme focussing on performance gains and long-term health. It isn’t just about extracting the most from your body at all costs, but more about keeping everything working well, improving health and well-being and improving performance at the same time. Relatively low intensity workouts, partnered with a fairly low carbohydrate diet reduces stress on your body, reduces inflammation and ultimately allows your to train consistently over long periods of time without breaking yourself down too much. Consistent, long term training leads to health benefits and performance gains too.

Finding your MAF heart Rate

In order to do true MAF training you need to calculate your MAF heart rate. This is simple using Dr. Phil Maffetones 180 method. The main points of which are summarised below:

To find your maximum aerobic training heart rate, there are two important steps. First, subtract your age from 180. Next, find the best category for your present state of fitness and health, and make the appropriate adjustments:

1. Subtract your age from 180.
2. Modify this number by selecting among the following categories the one that best matches your fitness and health profile:
   1. If you have or are recovering from a major illness (heart disease, any operation or hospital stay, etc.) or are on any regular medication, subtract an additional 10.
   2. If you are injured, have regressed in training or competition, get more than two colds or bouts of flu per year, have allergies or asthma, or if you have been inconsistent or are just getting back into training, subtract an additional 5.
   3. If you have been training consistently (at least four times weekly) for up to two years without any of the problems just mentioned, keep the number (180-age) the same.
   4. If you have been training for more than two years without any of the problems listed above, and have made progress in competition without injury, add 5.

So, for me that would be:

180 – 44 = 136bpm

I then fit into category ‘d’ above so would add 5. This makes my MAF heart rate 141bpm.

Too Generic?

This main problem with this method is that it is just too generic. OK, I realise that this will probably work for the majority of people, but at the same time, everyone is an individual and everyone is different. It’s a nice easy formula to use and will probably approximate a Maximum Aerobic Heart Rate for many people but I’m beginning to think that I’m an anomaly and that a true MAF heart rate just doesn’t work for me.

Lets look at a few other measurements and generic approximations that relate to training, heart rate and age and see how I compare to these.

Maximum Heart Rate

Maximum Heart Rate (HR_max) is the highest heart rate an individual can achieve through exercise stress and generally decreases with age. It can be measured through an exercise stress test but as it generally decreases with age there is a generic approximation used of 220 minus your age. So for me the generic Maximum Heart Rate would be calculated as:

220 – 44 = 176bpm

Now, I’ve never done an proper exercise stress test, but I have done plenty of tests in the Sports and Exercise Department where I work. I also wear a heart rate monitor for all of my training. Ignoring any spikes at the beginning of sessions due to a poor connection between my body and the heart rate strap, the highest I’ve seen my heart rate over the past few years is 164bpm. That’s 12bbpm lower than my theoretical maximum of 176bpm.

Admittedly the MAF zone is not based on HR_max but it is based on a constant minus your age in much the same way. The MAF heart rate can also be expressed as your theoretical HR_max  minus 40. We’ve already seen that my actual HR_max is 12bpm lower than my theoretical HR_max so surely my true MAF Heart Rate will be 12bpm lower than my calculated MAF heart rate too?

Lactate Threshold heart Rate

Lactate threshold (LT) (or lactate inflection point (LIP) or anaerobic threshold (AT)) is the exercise intensity at which lactate (more specifically, lactic acid) starts to accumulate in the blood stream. Lactate Threshold Heart Rate (LTHR) is simply the heart rate at which you reach your Lactate Threshold.

LTHR can be measured using blood samples taken during an exercise ramp test or non-invasively using gas-exchange methods. I have had this measured several times over the past few years and my LTHR is curently 145bpm.

The Functional Threshold Power (FTP) tests that I do on the turbo trainer also give me a fairly accurate LTHR too. Many training zone charts also use this figure and some even make theroetical approximations to it based on your Maximum Heart Rate. In these calculations LTHR is often considered to be somewhere around 90% of your Maximum Heart Rate. This would put my LTHR at 158pbm – again, much higher than my actual measured LTHR of 145bpm.

Rate of Perceived Exertion vs Various Heart Rates

Rate of Perceived Exertion (RPE) is measured on the Borg Scale. It is a simple subjective scale used to gauge an individuals level of effort during exercise and is usually expressed in the following way using 15 points from Level 6 through to Level 20:

• Level 6 – 20% effort
• Level 7 – 30% effort – Very, very light (Rest)
• Level 8 – 40% effort
• Level 9 – 50% effort – Very light – gentle walking
• Level 10 – 55% effort
• Level 11 – 60% effort – Fairly light
• Level 12 – 65% effort
• Level 13 – 70% effort – Somewhat hard – steady pace
• Level 14 – 75% effort
• Level 15 – 80% effort – Hard
• Level 16 – 85% effort
• Level 17 – 90% effort – Very hard
• Level 18 – 95% effort
• Level 19 – 100% effort – Very, very hard
• Level 20 – Exhaustion

We can use this scale to cross-reference the heart rates mentioned above. Starting from the top with the most uncomfortable:

Maximum Heart Rate would equate to an RPE of 19 on the Borg Scale.

Lactate Threshold Heart Rate would be somewhere around Level 15-16 on the Borg Scale. I like to think of it as the sort of effort where you really would like to ease of a little, but you don’t absolutely ‘need’ to ease off. It’s hard working at this sort of level but always rewarding because when you finish you feel as though you’ve achieved more than you thought you could.

MAF Zone Heart Rate would probably fit somewhere around Level 12. That’s to say a fairly steady pace that you should be able to keep up for several hours.

From experience and testing I can tell you what my personal heart rate would be at these levels on the Borg Scale too.

Level 19 would see my heart rate as expected hitting my measured maximum of around 164bpm.

Level 15 would see my heart rate at around 145bpm and therefore equates as it should to my measured LTHR.

Level 12 however would probably see my heart rate at around 125bpm, much lower than my calculated MAF Zone Heart Rate of 136bpm.

A trend is beginning to develop here that does indeed seem to suggest that I’m an anomaly. Whenever we use a generic, calculated heart rate such as the 220 minus your age for Maximum Heart Rate, 90% of Max for LTHR or 180 minus your age for MAF Zone Heart Rate. the numbers simply don’t match up for me.

As you can see, my actual heart rate seems to be around 12bpm lower than it ‘should’ be according to norms. With this in mind, a training plan based around a very generic calculated heart rate such as that of true MAF training simply won’t work for me. If I do true MAF training at 141bpm (as calculated by the Maffetone 180-method) I’ll actually be working a lot harder than I should be. In fact I’ll be quite close to my LTHR which will mean that I’m not getting the benefits I should from such a training protocol. I’ll be training in a heart rate zone no-mans land. I’ll still see fitness improvements but won’t be working on any one aspect of my fitness. In addition I’ll be stressing my body more than is needed and not getting the health benefits purported by advocates of MAF training.

What to Do?

So, what should I do? I have three options really.

One is to base my training on a different protocol such as that of Friel or Coggan. These base your training zones on actual measured heart rates rather than generic calculations. These tend to be more ‘traditional’ training programmes though with several harder, higher intensity workouts interspersed with easier recovery workouts, as opposed to an emphasis on easy, lower heart rate workouts of the MAF protocol.

The second is to stick to a MAF style protocol but not use true MAF zones calculated using the 180-method. Instead I should adjust my personal ‘MAF zone’ to align with my individual heart rate. Maybe I should simply use the 180-method as a starting point but then knock off 12bpm based on my table above to give me a MAF Heart Rate of 129bpm.

The third is to just forget the heart rate, forget lactate thresholds, forget Borg Scales and RPE’s and just get out there and enjoy it!

Maybe it’s time for me to develop a MAF-style training programme based on real-world measured heart rates rather than an arbitrary figure based solely on your age?

Tags: FTPLTHRMAFTrainingTriathlon