Heart rate formulas, how reliable are they?

I have been a bit of a runner for most of my life. Where I grew up in the Highlands of Scotland there was plenty of cross country running tracks to be explored. Of course that was mixed in with mountain biking, fly fishing, kayaking, sailing, football, hiking, rock-climbing… you get the picture.

I have decided to run a year of events for a cancer charity. You may have seen the social media posts floating around (link here). Whilst I’m out on my many various training sessions I often get time to chat to other runners or get to contemplate and consolidate my thoughts.

Recently, I was engaged in a lengthy conversation with another runner about training methods. Let me set the scene. We had just finished a swim of 1000m and a 5km run. We were cooling down with a short jog along the beach. The conversation went something like this:

Other runner: You’re certainly improving, I can see that you are climbing positions in the field.

Me: Thanks! I’m feeling a lot fitter and keen to keep progressing.

Other runner: Yeah, you’ll get there. Actually, we should get together some time and train if you like?

Me: That would be great! I am always keen to learn off others to improve my own performance.

Other runner: Well, if you are keen to improve your performance you might be interested in MAF training. I tried it and I feel considerably fitter since doing it.

Me: (For a split second my mind skipped to Married At First Sight training and then thought he must have made a mistake) Oh you mean MAP training? (not actually realising that I then would have to explain what my made up abbreviation actually meant!) What does it involve?

Other Runner: No no, MAF training (Phew humiliation of bullshitting averted!) Well, you minus your age from 180 (set as your maximum heart rate) and then aim to maintain the heart rate whilst gradually increasing your running speed. It’s really worked for me. I’ve been able to gradually increase my pace whilst maintaining a steady heart rate.

Me: Oh right, wow! How long did it take you to get to an optimum level?

Other runner: About a year…

After this we kind of chewed the fat about future events and meeting up for training together. So, MAF training eh? Now my usual go to thought for any ideas I get when running or when someone suggests something to me is, “How does it relate to pain management?” In any case, I decided to find out more about MAF training.

 

Off I went to scour the research search engines. Unfortunately, there is limited empirical evidence on the MAF method and upon reading Dr Maffetone’s white paper (Maffetone, 2016) the only supporting evidence is a poster he and his co-researcher delivered in 2015 (Hoeg & Maffetone, 2015). The notion behind the MAF method is to use the ‘180 Formula’ and adopt an optimal running gait… uh…whatever that is??

What is MAF?

It’s the abbreviation for Maximum Aerobic Function. The founder of the methodology, Dr. Phillip Maffetone, has worked in the field of ‘human biology, kinesiology, physiotherapy and Chinese medicine… is a pioneer in the field of biofeedback’.

Dr. Maffetone explains that the MAF method harnesses the body’s true aerobic or energy system which is the fat-burning system. He continues to explain that any impairment in the aerobic system can lead to global ill health problems in the body including diabetes, cancer, chronic heart disease or joint disease. This also qualifies for the trained athlete leading to injuries, lack of improvement and overtraining.

Dr Maffetone continues by recommending ‘a period of low-intensity training and natural movement (again, I have to ask, “what does he mean by natural movement?”) to improve aerobic function and health before embarking on higher-intensity training.’ His justification for this being that high intensity, short rest, high volume fitness programs may result in fitness gains but do not provide adequate health gains (referring to increases in metabolic and oxidative stress, decrease immune function, release of pro-inflammatory mediators etc).

So, the method of MAF focuses on improving the function of the aerobic system. To do this Dr Maffetone has developed a training formula based upon what he claims to be years of research and utilising the measurement of heart rate (HR). The 180 formula has been selected based upon the utilisation of correct substrates in this case fatty acids.

Why a 180 formula?

Dr Maffetone argues that once heart rate begins to exceed 150bpm this tips the body into  anaerobic threshold meaning that the body starts to burn sugar rather than fat.  Anaerobic function creates higher levels of biochemical stress, decreases immune function, increases inflammation and impairs fat burning. I suspect what he is referring to is prolonged anaerobic function…?

What I find particularly interesting is the sources of energy he refers to under an umbrella term ‘sugar’ all have an important role to play providing fuel for exercise. This includes, glycogen, lactate and blood sugar. Whilst they may all be related to ‘sugar’ each of these substrates are important. Take lactate for example, sprint training is part of a long distance runners exercise repertoire. Lactate can actually be metabolised to produce ATP (the bodies energy molecule). Sure, there appears to be agreement that fat is the bodies richest fuel source. However, anyone reading may not be surprised when I say the body is highly adaptable and has been known to shift energy utilisation based upon the most abundant fuel source (Volek, Noakes, & Phinney, 2015).

As Dr Maffetone claims, a heart rate above 150bpm appears to purely utilise the process of anaerobic glycolysis (sugar based fuel utilisation) rather than fat. The formula is displayed below:

180 – (persons age) = (target HR)

Dr Maffetone acknowledges the idiosyncrasies in individuals fitness and health and so provided additional instructions for HR monitoring:

a. 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.

b. If you are injured, have regressed in training or competition, get more than two colds or bouts of flu or other infection per year, have seasonal allergies or asthma, or if you have been inconsistent or are just getting back into training, subtract an additional 5.

c. 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) as maximum.

d. If you have been training for more than two years without any of the problems listed above, and have made progress in athletic competition without injury, add 5.

 

The MAF assessment and additional instructions are claimed to have been devised following “years of clinical assessments.”  Although, Dr Maffetone’s reasoning for why specific training at low intensity has empirical evidence his 180 formula lacks efficacy. I want to briefly highlight my issues with such a stringent method that seems to demonstrate a large margin of error.

 

We know very little of Dr Maffetone’s work except for the fact that he has conducted “years of clinical assessments.”  Questions that immediately spring to mind include:

  1. Do we assume that all his clinical assessments were in laboratory setting? He does state that a running test should be done on a 400m track. I don’t know many that have access to this facility.
  2. How did he set up his clinical assessments?
  3. Did he accommodate for huge variation comparing running terrain, footwear, temperature, the elements (wind, rain, heat, cold), competition vs recreational, body type, genetics, previous exercise history, sleep, diet, resilience, pessimism vs optimism, behaviour, culture? The list can go on as I’m sure you understand.
  4. Further to point 3, how can we continue to think that a univariate formula will accommodate multivariate differences such as gender, development, health, socio-economics etc.
  5. He discusses biomechanics as if there should be an optimal way to run but how can you accommodate for that particularly with reference to the above factors and that much of the evidence has refuted the theories of biomechanics.
  6. What did he compare his formula too? He states that his 180 formula is not a replacement for executed laboratory tests… although it usually corresponds with them.
  7. There has been a significant amount of research published supporting the effects of resistance training and high intensity exercise on chronic disease such as diabetes, metabolic syndrome, cardiac related problems. This type of training utilises fast twitch fibres and primarily the process of anaerobic glycolysis where lactate and glycogen are utilised as a fuel source (Sullivan & Baker, 2017). So, does this refute Dr Maffetone’s proposal that low intensity exercise is a better option to utilise fat as a fuel source?

Overall, there are a number of problems with Dr Maffetone’s reasoning. In particular, and with all heart rate equations, the yardstick he uses is univariate. Human beings are not univariate. Multiples systems are working at once and we have to consider context in all circumstances. He uses heart rate to justify a method, yet individual heart rates in chronic disease or exercise with this method is so arbitrary it can be difficult to broadly apply the method to individuals that may be of the same age or health/fitness level etc. As mentioned above, there are too many variables to consider.  I respect that it did work for the guy I chatted too, however I did not probe enough into how he performed his training and I suspect that he trained for one particular sport. Due to the lack of evidence and what I have highlighted above, I remain sceptical.

Following this investigation of the 180 formula I decided to continue reading around other maximum heart rate (MHR) formulas, in particular the Karvonen method and to discuss its utility in pain management strategies such as exercise induced hypoalgesia (EIH). I admit this is a rather large and complex area of research and the evidence base is extensive. I do my best to cover what I believe is derived from current evidence. However if anyone reading this wants to share their knowledge then please leave a comment.

Maximum Heart Rate Theory?

The most frequently used formula for identifying maximum heart rate is the age predicted method of HR max (220bpm – age). Typically, training zones specific to the fuel source are then calculated using a percentage of heart rate. (see table 1).

 

 

The familiar heart rate HR max formula of 220 – age is ubiquitous throughout healthcare. After a bit of digging around, I found that the 220 formula has been subject to quite a bit of scrutiny. Predominantly, its utility has been in the 60+ age group because of the prevalence of heart disease in this population.

Yet, the MHR formula, despite being a cornerstone, is contentious and may not be appropriate to population groups not living with heart disease. Like a lot of things we are identifying (posture, lifting, sitting, movement), context has a profound effect on our physiology.

It turns out MHR was not based on original research and was more an observation derived from 11 references by one of its founding physicians – Fox and Haskell (Robergs & Landwehr, 2002). Robergs & Landwehr, (2002) explain in their paper that most MHR formulas have no scientific merit due to large prediction errors. This is because MHR formulas represent an age-based univariate prediction equation. Studies have shown the 220 – age equation fails to provide adequate measurement of heart rate training zones with variation of up to 12 beats per minute (Black et al., 2017; Sluka., 2016). The interactions within humans and with context are not univariate as we are well aware from research in causation (Evans, Lucas, & Kerry, 2017). Heart rate itself does not remain at a steady state it has multiple fluctuations based on context.

This is crucial information particularly if the physiotherapy profession’s stance is firmly within exercise. I have been witness to, and engaged in, many conversations regarding exercise erroneously represented as the panacea for chronic disease, injury and even pain management. Commonly, we use aerobic exercise prescription as a management approach. There is a high consensus that the axiomatic formula for prescribing aerobic exercise is to use HRmax = 220-age. Please note this is not universally so much as significantly used.

The Karvonen method

Named after the Finnish physiologist and also known as Heart Rate Reserve, the Karvonen method calculates the lower- and upper-threshold HR levels at a percentage of the difference between resting and maximum HR.

The formula is expressed below:

  1. Calculate predicted HRmax

HRmax = 208 – 0.7 x Age

  1. Calculate LLthr:

LLthr = [(HRmax – HRrest) x 0.50} + HRrest

  1. Calculate ULthr:

ULthr = {(HRmax – HRrest) x 0.85) + HRrest

The Karvonen method was developed to consider the additional variable of HRrest as well as age, which is the main variable in the 220 equation. It also aims to optimise heart rate range between 50 and 85% of maximum heart rate.  You may have noticed that the HRmax is 208bpm. The Karvonen method was traditionally used with the popular 220 – age equation. A paper by She, Nakamura, Makino, Ohyama, & Hashimoto, (2015) selected a series of heart rate formulas for use with the Karvonen method to calculate exercise intensity in male university students. They author found the traditional 220-age equation and the formula proposed by Miller et al., (1993) (HRmax = 217 − 0.85 × age) to be most suitable for 20 year old males.

Also included in She et al’s paper, researchers Tanaka, Monahan, & Seals, (2001) conducted a meta-analysis investigating where gender or habitual physical activity status had an influence on HRmax – age relation. The results of their study obtained the regression equation of 208 -0.7 x age to predict HRmax. Interestingly, they found that ‘HRmax was strongly and inversely related to age in both men and women and when all subjects (sedentary, gender, active and endurance subjects) were combined the regression equation was 208 – 0.7 x age.’ They also compared the traditional 220 -age equation with the regression equation and identified that ‘the traditional equation overestimates HRmax in young adults, intersects with the present equation at age 40 years and then increasingly underestimates HRmax with further increases in age.’ So, use of 220 – age in younger and older age populations would appear to create issues around heart rate training zones. However, what with the fluctuations in heart rate in relation to context, using heart rate may be futile. Thus the use of subjective ratings of exertion (RPE) such as tiredness, difficulty, out of breath may be a better measure as eloquently explained by Gunnar Borg back in 1982 (Borg, 1982).

Exercise Induced Hypoalgesia

Does this mean that heart rate measurement (such as the equation from Tanaka et al) can be used as a means to promote EIH?

EIH has been shown to occur with resistance, isometric and aerobic exercise. Regardless of the type of exercise, pain relief following exercise is systemic. This has been repeatedly shown in healthy subjects (Black et al., 2017; Sluka, 2016). Studies have shown VO2max as the preferred means to determine appropriate percentages of exercise intensity for promoting EIH. Naugle, Fillingim, & Iii, (2012) conducted a meta-analytical (MA) review of the effects EIH in aerobic and isometric exercise. They examined the literature in “healthy” subjects and individuals living with chronic pain. The studies selected in the MA review identified a percentage of 75% of VO2max (moderate to high intensity) whilst exercising for 30 minutes (healthy subjects) was effective in promoting EIH. This is also supported by Sluka, (2016). In chronic pain subjects percentage of VO2max range from 50-70% (low to moderate) with exercise duration ranging from around 10 – 30 minutes. The caveat here is that EIH did not occur in individuals with chronic widespread pain and only in those with regional chronic pain conditions.

Whist Naugle’s MA review did highlight a percentage of VO2 max and duration of exercise at varying intensities, it was still difficult to determine the appropriate dose of exercise to produce hypoalgesia.

We can see that dosing exercise to produce EIH is a challenge. Measuring VO2max is also a challenge as it requires specialised laboratory equipment which is not readily available clinically.

What of using HR as a means of producing EIH? Is there really any point? It is still worth exploring how we might be able to promote EIH clinically using HR equations. Heart rate monitors are readily available with the explosion of wearable biofeedback technology.

A number of methods have been derived from VO2max and HRmax regression equations including that of Tanaka et al (2001). Non-exercise equations and heart rate predictions have been the basis of studies in an attempt to identify appropriate exercise intensity levels for a range of population sub-groups (Barboza, dos Santos Nogueira, & Pompeu, 2017; Rexhepi & Brestovci, 2014; Uth, Sørensen, Overgaard, & Pedersen, 2004). However, the VO2 estimation equations are incredibly complicated and if you’re like me who has a fear of maths equations it’s likely something that you won’t see the point of doing clinically. For your interest I’ve attached one of the equations below

So it would seem, the variability in heart rate, the challenge of reliably measuring heart rate,  the multifactorial nature of pain, the individual differences of populations and the effect of context make producing EIH clinically kinda difficult. That doesn’t mean we shouldn’t try. Clinicians need to consider a broader context of factors when implementing exercise principles.

A reflection I can take away from my reading is that using the traditional HRmax equation (220 – age) may only be effective for specific population sub-groups and that using the HRmax regression equations, developed by Tanaka et al may provide more reliable heart rate training zones in various age populations. As for individuals living with persistent pain, perhaps identifying what their HRrest is prior to commencing exercise and using the adapted Karvonen method could prove useful. In addition, determining what their exercise levels are, what psychosocial barriers are present and what is of value in terms of activity in their lives may provide a more appropriate means of determining an adequate heart rate training zone and may facilitate some apprehension towards the dread flare up that frequently occurs following activity.

Summary

So, to go back to the 180formula. I remain sceptical. Dr Maffetone in his wisdom highlights some additional messages that I feel are nothing short of plain common sense.

  1. Working at a lower intensity is easier for the body and utilises the aerobic fat burning system.
  2. The message that health is not the same as fitness.

My own thoughts are as follows:

  1. Due to the variability of heart rate, the challenges of adequately measuring heart rate, the individual differences of humans, the varying environments that people train, changes in health status, sleep issues makes monitoring heart rate training adequately incredibly challenging.
  2. The impact of psychosocial barriers needs to be factored in to Dr Maffetone’s work if he is to provide any form of reliable HR measurement for adequate training.
  3. Personally, I think listening to your body and the use of RPE is altogether a better method.

A final thought would be the all too familiar message of ‘one size does not fit all’ is highly appropriate. As for the 180formula, I will remain sceptical.

Thanks for having a read.

TNP.

 

References

Barboza, J. A., dos Santos Nogueira, F., & Pompeu, F. A. M. S. (2017). A New Accurate Model to Predict Maximal Heart Rate. Journal of Exercise Physiologyonline, 20(5), 23–28.

Black, C. D., Huber, J. K., Ellingson, L. D., Ade, C. J., Taylor, E. L., Griffeth, E. M., … Sutterfield, S. L. (2017). Exercise-Induced Hypoalgesia Is Not Influenced by Physical Activity Type and Amount, (9), 975–982. https://doi.org/10.1249/MSS.0000000000001186

Borg, G. A. (1982). Psychophysical bases of perceived exertion. Medicine and Science in Sports and Exercise, 14(5), 377–381. https://doi.org/10.1249/00005768-198205000-00012

Evans, D. W., Lucas, N., & Kerry, R. (2017). The form of causation in health, disease and intervention: biopsychosocial dispositionalism, conserved quantity transfers and dualist mechanistic chains. Medicine, Health Care, and Philosophy, 0(0), 0. https://doi.org/10.1007/s11019-017-9753-6

Hoeg, T. B., & Maffetone, P. B. (2015). The Development and Initial Assessment of a Novel Heart Rate Training Formula. Wilderness & Environmental Medicine, 26(4), e5. https://doi.org/10.1016/j.wem.2015.03.016

Katch, V. L., McArdle, W. D., & Katch, F. I. (2011). Training the Anaerobic and Aerobic Energy Systems. In Essentials of Exercise Physiology(4th Editio, pp. 409–442). Lippincott Williams & Wilkins.

Linda S Pescatello. (2014). ACSM’s guidelines for exercise testing and prescription 9th ed. 2014. Philadelphia : Wolters Kluwer/Lippincott Williams & Wilkins Health, ©2014.https://doi.org/10.1017/CBO9781107415324.004

Maffetone, P. (2016). White Paper: MAF Exercise Heart Rate. How it can help improve health and sports performance.

Naugle, K. M., Fillingim, R. B., & Iii, J. L. R. (2012). A meta-analytic review of the hypoalgesic effects of exercise. The Journal of Pain, 13(12), 1139–1150. https://doi.org/10.1016/j.jpain.2012.09.006.A

Rexhepi, A. M., & Brestovci, B. (2014). Prediction of VO 2 max based on age , body mass , and resting heart rate, 15(1), 56–59. https://doi.org/10.2478/humo-2014-0003

Robergs, R. A., & Landwehr, R. (2002). THE SURPRISING HISTORY OF THE “HRmax=220-age” EQUATION ROBERT. Journal of Exercise Physiology Online, 5(2), 1–10.

She, J., Nakamura, H., Makino, K., Ohyama, Y., & Hashimoto, H. (2015). Selection of suitable maximum-heart-rate formulas for use with Karvonen formula to calculate exercise intensity. International Journal of Automation and Computing, 12(1), 62–69. https://doi.org/10.1007/s11633-014-0824-3

Sluka, K. A. (2016). Mechanisms and Management of Pain for the Physical Therapist(Second Edi). Philadelphia: IASP Press.

Sullivan, J. M., & Baker, A. (2017). The Barbell Prescription: Strength Training for Life After 40. The Aasgaard Company.

Tanaka, H., Monahan, K. D., & Seals, D. R. (2001). Age-predicted maximal heart rate revisited. Journal of the American College of Cardiology, 37(1), 153–156. https://doi.org/10.1016/S0735-1097(00)01054-8

Uth, N., Sørensen, H., Overgaard, K., & Pedersen, P. K. (2004). Estimation of VO2max from the ratio between HRmax and HRrest – The heart rate ratio method. European Journal of Applied Physiology, 91(1), 111–115. https://doi.org/10.1007/s00421-003-0988-y

Volek, J. S., Noakes, T., & Phinney, S. D. (2015). Rethinking fat as a fuel for endurance exercise. European Journal of Sport Science, 15(1), 13–20. https://doi.org/10.1080/17461391.2014.959564

11 Comments

  1. Thank you, Naked, for this article. I had initially been quite intrigued by the MAF method but should’ve been more cautious given its cult-like following. These days, I generally go quickly to research papers, being untrusting of most popular simplifications or oldwiving of concepts that have actually been scientifically researched. (Being a scientist, that comes easy to me.) However, with MAF, I initially overlooked doing that as a quick glance seemed to suggest that he had written several peer-reviewed scientific articles and was a researcher himself. My mistake. You are right, the Hoeg and Maffetone 2015 abstract is all I could find as well that looked like hard clinical evidence for anything advocated by Maffetone, but even that abstract seems either internally inconsistent or erroneous, claiming that in group 2, 42 of 42 participants completed the study while the introductory para says group 2 had respectively 38 participants with gait-based HR assigned and 39 as control. I couldn’t find any further details of how exactly this study was conducted, and the presentation of the abstract doesn’t give me much confidence.

    I couldn’t find anything else by Maffetone that even tries to seem like a peer-reviewed scientific article (as opposed to a white paper, qualitative survey, or marketing article). It seems to me that the allure of injury prevention, “fat burning” for the weight loss crowd, and “mental vigor” and overall well-being feels to tempting to resist for many of his followers, but is little different from most new-agey hogwash.

    Liked by 1 person

    1. Hi AV,
      Thanks for the message and your comments. Hogwash is certainly an appropriate term I would use at this moment in time. Naturally (as I am sure you would be) if there was further evidence to provide a credible argument for this method I would be intrigued. However I am unsure of how you would structure a methodology that could be extrapolated to the general public due to the significant influence context has on human functioning and behaviour (inc heart rate). As it stands (like anti-ageing creams) it is a capitalistic driven agenda to prey on the vulnerable and intrigue the athlete to gain the extra edge with no substantial support behind it.

      All the best.

      Like

  2. Good evening Naked, An intriguing post that will appeal to anyone who has come across MAF but retains an open mind. As far as assessing aerobic threshold is concerned, you might be interested to look at work by Gronwald, Rogers and Hoos in using detrended fluctuation analysis of heart rate variability to determine exercise intensity distribution. On the tech side, data scientist and exercise expert Marco Altini has developed an app for experimental use. He claims, convincingly, that this is a much more individually tailored way of arriving at exercise thresholds, which will vary in the same individual over time due to stress. All still in the early stages, but sounds promising. More good empirical science is what we need https://www.frontiersin.org/articles/10.3389/fphys.2020.550572/full
    and
    https://www.marcoaltini.com/research–publications.html

    Like

    1. Hi Ben
      Thanks for having a read and the referencing. I look forward to reading. I’m intrigued with respect to you insights. HRV is something that I have played with in my clinical practice with people living with chronic pain. I find it useful more from a visual feedback, however I also find people can become frustrated wihen their readings don’t appear to match how they are feeling subjectively. Thus I have reduced it’s use for inconsistency. Be keen to hear your thoughts.

      Cheers

      Like

  3. Well, it’s official, at 47 my lactate threshold is at around 181-185ish. My walking HR is around 110-135 in flat terrain, and has been for years. Every bit of running immediately gets be above 155 (my vt1). I laugh at those eqations.

    Like

    1. Hi Nina, I’m in the same situation. All of the stuff about 80/20 polarized training, pyramidal training and what not feels utterly useless to me as my HR goes up to 90% of max within a mile or so of relatively (perceived) easy jogging.

      If I run idiotically slow (like 12 min miles), I can stay just under my threshold HR (as estimated by my running watch and happens to be around 80% of my max HR and around 85% of my reserve HR (max – resting)).

      Like

      1. Have you set a custom HR on your watch? It’s quite possible that you simply have a higher than average maxHR. 220-age, which pretty much all devices use as standard only work for about 70% of the population assuming a standard distribution. If you’re on of those 30% then you really need to use custom settings.
        I have custom settings with a maxHR of 209. I’m a woman of 47 as I said above, thus it’s a bit unusual. But part of my inability to keep my HR low when running is likely related to something from the dysautonomia spectrum. It’s not PoTs as my HR reacts to changes in intensity and looks fairly normal within my range to 209 when cycling. Things do go wrong when running or when anything uphill is involved. Shrugs.

        Like

        1. Hi Nina, thanks for the tip. I use a Coros watch (that I mostly quite like) that allows me to input a max HR and I input 188 into it because that is the maximum HR I have ever observed on that watch during my training, some of which involved all-out hard runs. I haven’t taken a max HR lab test, but my Apple Watch has measured a max of 191, and both Apple and Coros are within 3-5 beats of a chest strap that I have also used. My Coros also has two modes of running zones: one based on percentage of reserve, and based on percentage of max HR, but with either one of them, even if I jog comfortably at a pace I can sustain for 30+ minutes while breathing only through my mouth, my HR goes to the upper end of Threshold or to Anaerobic. My average HR often goes over 170 and almost always over 165 on 30+ minute runs irrespective of my speed, so the only long runs I can do also have to be threshold runs, or so it seems (or I need to walk intermittently). I don’t actually start feeling drained until 175, a HR that I know is hard to sustain for me beyond 20 minutes or so.

          Glad to hear your max is 209 at 47. I am guessing my max is around 200 or more too but am afraid to find out. I am in my early forties and, exactly once while cycling my Coros reported 206, but I decided to ignore it as the ride although uphill wasn’t all that strenuous and my HR while cycling never goes over low 180s and even that only on an uphill torture ride.

          Being able to jog meditatively for an hour at 155 feels like a heaven I can only dream of.

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  4. Hi Naked, do you know of research on how to train, especially for recreational runners, in order to be able to run *at all* for 30-60 mins while maintaining a heart rate that is fairly lower than ~90% of max? Or equivalently, how to train so that your HR over weeks and months of training reduces for the same pace. I find that I have to run unnaturally slow to prevent my HR from creeping up to the supposedly anaerobic zone within a mile or so. Although my rate of perceived exertion feels less than my HR suggests, a lower HR does feel even more easy, so while HR is just a number not worth obsessing about much, I’d like to run longer while feeling easy at my normal jogging pace.

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  5. I too was cynical of the general formula and I said most of the comments above about individualisation, about “my HR is just too high for that” for years. Yes I was happy to reduce my intensity and easy training HR but not to that low a level which was almost impossible. However, Dr Maffetone’s credentials are good and there are successful athletes who have benefitted from his approach. I prefer low carb diet anyway, so the thought of investing in my aerobic system and employing less glycolytic metabolism in training was attractive. At the start I had to run dead slow. A combination of running and walking any hills. Careful nose breathing, careful form.
    1 month in, my average km pace (at 180-age HR) has already dropped by 25 seconds. I’m really enjoying running this way and have run more than in years. I generally feel much better physically and mentally too.

    I’m not 100% convinced that the formula is optimal for me, but I’m following the principle that it’s better to be a bit lower than a bit higher until my aerobic system strengthens.
    Next month I will try to do a drift test or similar to estimate it more accurately.
    In a couple of months I’ll add in some threshold runs but not too much.
    Much yet to discover but maybe I should have been less cynical when I was younger and my MAF formula was higher.

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  6. Interesting comments above (and in the article)… a couple of thoughts from someone who has monitored and/or trained with HR methods for nearly 20 years now.
    First, re: MAF method – I have to agree with the concerns about it being very “univariate”… but I think in large part it’s so conservative as to be a “can’t really go wrong” formula. I’m a well-trained athlete for my age (49 going on 50), and MAF at 130, slots right in at the top end of my Karvonen Z2 calculation. (Resting HR I use is 42, although it dips into the high-30s on some days it’s consistently no higher typically than 42).
    Which brings me to the article discussion on Karvonen – there is a slight error in understanding (IMO) regarding Karvonen, and that’s the mention of Tanaka and estimated Max HR. This isn’t directly associated (although the Tanaka formula IS better, to my mind)… in reality for ANY HR “zone training” the real method is actually testing it, not estimating it. And if you KNOW your max HR for Karvonen (or even the simpler MaxHR*% method), your numbers are going to be more reliable for ANY method. My issue with the article is that it assumes people only use “estimation formulas”… those are ONLY to be used, in the absence of a well-performed MaxHR test because of the potential variability.
    This then brings up the next challenge and acknowledgment. The author indicates well that actual availability of reliable HR testing is a challenge (but monitoring in general isn’t, HR trackers are relatively cheap and easy now built-in to many watches, phones, etc).
    Regarding MaxHR testing, in the comments someone mentioned using a number because it’s the “highest they’ve seen when working out” on their watches, etc… that is NOT a max HR selection. It’s better than nothing of course, but any normal workout doesn’t test max HR, and this is a common mistake. MaxHR is a rigorous, painful to obtain value, you have to test with purpose to attain it, and the test itself (different forms exist) typically only takes 10-15 minutes in total, and most of that is just warming up to prevent injury during the testing. If someone wants a “DIY” max HR test with a suitable heart-rate monitor, find the steepest hill you can find in your area to run up… warm up 10-15 minutes at a relatively easy pace (you do NOT want to exert too much energy warming up, just getting loose and getting the blood flowing)… now, run up the hill for 30 seconds at about 80+% of what you “feel” is your max effort…. at 30 seconds slow and turn around and walk or very easy-jog down the hill, this should take 1-2 minutes…. now turn around and run up that hill again harder, trying to get 90%+ effort…. you should be putting out a LOT of exertion to keep the same pace after 30 seconds that you were when you started at the bottom…. now turn around again and easily return to the bottom again… this time, run all-out as fast as you possibly can go but still keeping it up for the full 30 seconds… if you hit 30 seconds and have anything left go even harder for as long as you can (if you are nearing the top of the hill in that 30 seconds, turn around for one more repeat, and do a 4th cycle, even harder the 4th time). You should be absolutely unable to maintain more than a couple of steps after the 30 seconds passes before you physically must slow down…
    You may not get the test right the first time you try, if you go out too hard, your oxygen and circulatory systems may not both get fully up to speed in time, causing one to artificially limit the other one… if you go out too easy, you can end up with your muscles beginning to tire and/or start accumulating lactic acid, before you actually reach your max HR…. so the goal is to achieve the max HR before your muscles start giving out, and you should have NOTHING left on the last repeat, basically not able to do more than walk slowly to recover afterwards. Again, this whole test, the “max effort” portion, shouldn’t take more than about 8 minutes, otherwise you’ve missed the mark.
    Final issue mostly in the comments, many people talking about how their efforts are putting their HRs into higher thresholds than they’d expect… these comments are putting the cart before the horse… the whole point of low HR training such as MAF, or Z2 methods in other zones, is to actually counteract that problem… how fast you go is irrelevant, stay in “zone 2/MAF zone” for your workout, period… (I used to make these same mistakes before I began adopting some z2 training methods and finding out they really work)…
    I’d complain that “Z2 is basically walking!!!!” First mistake, I was using the “% of Max HR” formula which, today, has my Z2 at 103-120… one day I discovered Karvonen, which solved that problem (Z2 = 119-131)… it was still “very slow jog, and walking on uphills” in the beginning… what happens though, is your speed increases as you train… suddenly those “12min/mile” Z2 workouts, a year later, are 10:30/mile… and HR hasn’t moved… you’ve become more fit, more efficient, and “less overtrained”…. and the magic is happening. It does require trust, I literally picked a year and said “okay, I’m going to give this a shot for at least 6 months and see what happens”…
    I then adopted some formal Polar training programs, which aren’t exclusively low-zone (like MAF would indicate), but are still mostly 80/20 (80% Z2, 20% “above Z2” in volume of training intensities)… That year my half marathon pace improved from 2:10, to 1:56 the following year, and in just over a year span, I did 2 marathons, first was nearly 6 hours, the next was 4:14…
    Oh, and in my last marathon (I’ve only done those 2)… I actually set PRs during that marathon for my 1 mile, 5k, 10k, and half marathon times while doing the actual MARATHON (which I was way faster paced in the first half, probably too much, as calf cramps killed me at around mile 19 and I spent a few miles walk/jog/hobbling, LOL)
    All this to summarize… .low HR training can work well… and if a person uses a truly TESTED Max HR as the basis for their formulas, nearly all of them work “better” than any estimations (which the % of max, combined with estimated age-220 is wildly wrong for me). I actually am close to the estimated “age-220” and Takana formula as well, my actual max HR is 173, the problem is the “% of max” formula doesn’t work for me at all, Karvonen was the magic fix for my zones to match RPE, and to benefit with the “described” training responses matching the zones they were supposed to.

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