An Inconvenient Truth: Why Heart Rate Always Matters

Stay the CourseI have written about heart-rate physiology and training before in ‘Stay the Course.’ While heart-rate training has been the gold standard of exercise prescription for decades, it continues to come under scrutiny from trail ultrarunners, and more notably from some of the sport’s most prominent coaches, who believe that heart rate is too highly variable to be a reliable training guide. I think they are wrong, and here is why.

Heart-Rate Basics

What it is.
Heart rate is a form of biofeedback that correlates to physiological workload. The theory is, the faster the heart beats, the harder the system is working to provide the system with the required physiology–water, oxygen, and nutrients into tissues; and carbon dioxide, acid, and byproducts out of tissues.

How it’s measured.
Most modern GPS watches come with either a chest or wrist heart-rate monitor, which uses either electrical or optical technology to measure pulse rate (in beats per minute). Late-model heart-rate monitors can often read erratically, especially the early generation wrist monitors. But the technology is improving and the readings are increasingly accurate.

Why monitoring exercise physiology matters.
Most runners and coaches agree that optimal fitness requires training different physiological–or energy-utilizing–systems. These systems include:

  • Anaerobic alactic— This is a short-lasting system that delivers energy for tasks under 10 seconds. It uses leftover energy that is sitting around in the muscle cell. It does not require oxygen–and does not produce byproduct waste–because it is already produced.
  • Aerobic— Fat metabolism, where the body uses predominantly fat as fuel, is the desired energy system. Always. For everything. The reason is that fat metabolism is a more efficient, less stressful physiological process than glucose (or glycogen, or exogenous sugar) metabolism. In fact, a key metabolic byproduct of fat-burning, β-hydroxybutyrate, acts as a protective shield against cellular damage.
  • Anaerobic lactic— This fast-acting, oxygen-less energy system utilizes glucose sugar only. While it is fast acting and highly powerful, it is also extremely stressful. Cortisol hormone, a pro-inflammatory stress hormone, is released in significantly greater amounts during higher-intensity, sugar-burning exercises. Other pro-inflammatory waste products include lactate and hydrogen ions (creating a more acidic cellular environment), and pro-inflammatory cytokines.

Optimal fitness development is the art form of balancing the slow-but-steady aerobic and powerful-but-stressful anaerobic systems. And because these energy systems run on a mixed continuum, precise monitoring of energy systems can be complex and difficult.

Energy-System Selection

Energy-system selection is based on far more than speed and distance.
A major error made by runners and coaches is the assumption that only training load impacts energy-system selection. In other words, they believe that training intensity and duration, alone, impact the degree of aerobic and anaerobic systems are activated in the body.

This is incorrect, because the body has other concerns besides the length and pace of your run. It has to balance the demand of your run, in addition to the other demands and threats it perceives outside of running, in order to keep you alive! And this is a tougher balancing act than most realize.

Exercise energy selection is feed-forward, not just feedback. Conventional physiology theory is that we are reactive species: we exist, we do something, our bodies react. This represents a feedback operating mechanism.

So for running, a feedback response would be:

Feedback response chart

But the key to optimal performance, and the key to human survival throughout our species’ evolutionary history, has required a system dramatically faster and more responsive than that. A feed-forward system is a system that tries to anticipate our needs far before we need them!

Consider this scenario: we are walking through the jungle and a lion crosses our path.

Under a feedback mechanism, the following would occur:

Feedback mechanism chart

Does this mechanism seem like a sound survival strategy? Seems a little sluggish, doesn’t it?

What happens instead is a pure feed-forward mechanism. The micro-second brain processing of the sight of the lion instantly activates all energy systems, including the anaerobic system, into full force:

  • High heart rate (up to 180 beats per minute within a few seconds)
  • Heavy breathing
  • Maximum neurological and metabolic activation of extremity muscles, in order to flee

Then, we get the hell out of Dodge!

This represents a feed-forward mechanism: the body (via the Central Governor, the executive of all physical activity) deciding how to act, far before we take that first step! This means that energy systems are activated before we even use them.

So those times when we think we see a lion (or perhaps a rattlesnake on the Western States trail), but are mistaken, we jump away, startled. Only moments later, when the conscious brain kicks in, do we stop fleeing. But as we’ve all experienced, the system remains activated (pulse rate, heavy breathing), at least for a short while.

This is the law of survival, the reason we’ve outrun the lions, tigers, and bears all these generations. The anticipatory feed-forward system is the law the dictates the vast majority of our exercise physiology.

This same design occurs during running, but usually to a far-more-subtle degree. The body can become relatively hyperactive, due to a number of factors besides the actual running pace. In fact, any potential stressor that the body deems relevant to survival–stress, fatigue, illness, the environment–may potentially change what energy systems are activated in any given run. It all counts!

The Hidden Costs of the Energy False Alarms

Thankfully we’re not always running from lions, but our bodies often behave that way. Life throws us many false alarms. Consider this analogy:

The alarm rings at the fire station. Without hesitation, the firefighters reacts. A score of men quickly but precisely assemble, dress, organize, load onto the truck, and blast out of the station.

Have they yet seen the flames or felt the heat? Not at all. They activate based on their perceived necessity signaled by the alarm. So when they arrive at the prescribed address, only to find only a small brush pile burning–or perhaps no fire at all–is there a cost associated with their activation?

Despite the false alarm, a finite and significant amount of resources have been preemptively spent: water, gasoline, even the calories ingested and burned by the firefighters in the preparation to battle the anticipated blaze. All the systems were activated and, while some of them may be put away, unspent, there is a sunk cost to that summons, and it is significant.

This is the mechanism of the day-to-day human stress response. Our fight-or-flight system often activates without any actual demand. When we get ‘stressed out’–engaged in a heated argument, mulling over a burdensome worry, or simply sitting in traffic–seldom is any physical task being undertaken. But the body is being activated. The engine is revving higher and tremendous sugar–the preferred fuel of fight-or-flight responses–is burned when under psychological stress, which is a major factor in ‘stress eating!’ We function as if we’re fighting an intense battle.

Therefore, when runners and coaches claim that factors impacting heart rate such as stress, environment (temperature, humidity, allergens), anxiety and nervousness, and caffeine and other stimulants do not elevate heart rate in a way that’s significant to the body’s physiology, they are mistaken.

Stressed out and going for a run? Your body will perceive the cost of that run as higher (because it is already dealing with your life stress) and will activate a more intense energy system to cover all the demands. More energy cost!

Anxious and nervous before the big race or workout? The Central Governor will recruit a more intense system to ensure your survival. More energy cost!

Experiencing allergies? Allergies like pollen represent an added immune-system threat, and the body will recruit more energy to overcome them. Again, more energy cost!

Taking caffeine and other stimulants? These artificially amp the system. Yep, more energy cost!

Think about your big race? Your heart rate–and total physiology–will amp up, because parts of your brain believe you’re actually racing! More energy cost!

These factors cause fire dispatch to signal a five-alarm fire for a given run on Long Run Lane when perhaps only one or two alarms were necessary. It’s because the dispatcher is sending extra engines for the smaller adjacent fires on Stress Street, Anxiety Avenue, and Allergy Alley! That those extra resources weren’t fully deployed to the run is irrelevant to the system. That higher energy system was activated and whether you ran hard or not, the fuse was lit and there is a cost to that deployment.

When the brain perceives a threat–real or not–a more intense energy system will be activated regardless of your actual running effort! You may not have punched out your boss during that heated argument, but your heart, lungs, nerves, and muscles are ready just in case! Likewise, when it is hot, humid, or the air is pollen-strewn, or you’re tired, stressed, anxious, and strung out, the energy cost is higher for the same running pace in ideal, relaxed conditions.

Elevated heart rate is seldom aberrant. It signals the entire body is ramped to another level of intensity to handle the added threats. More threats, more energy. More cost.

This means that your eight-minute pace at 160 heart rate–adversely impacted by the environment, anxiety and stress–has very nearly the same cost as your 6:30 pace at 160 heart rate under ideal conditions.

It all counts!

The Fallacy of Rate of Perceived Exertion in Trail Ultrarunning

Most coaches use Rate of Perceived Exertion (RPE) as a guide for exercise intensity. It is based on a scale developed in the early ’80s to help quantify perception of effort. The early studies of RPE were based on controlled studies of subjects exercising… in monotonous environments: treadmills, usually, but also exercise bikes and (if lucky) outdoor tracks.

Running, on the other hand, is extraordinarily variable. Ask any runner the mental difference between a flat pavement run amongst rush-hour traffic versus a solitary jaunt along the high-country ridges of the Western States 100 course. The same physiology may feel much different in different physical and psychological circumstances–and this is a huge factor in trail ultrarunning.

Because RPE is ‘perceived’ by the brain, enjoyment–and myriad other psychological factors–heavily influence RPE, including:

  • Surroundings. Beyond physiological activation, the physical environment of our run may play the largest role in determining RPE. A beautiful, sacred landscape has immeasurable dampening effect on RPE.
  • Community. With whom we run impacts RPE. Runners in a group tend to run significantly faster, with a lower RPE, than solo runners. This is the primary reason runners train and race intensely in groups. It’s simply easier.
  • Context. Running in special areas–either in parks, or in historic trail races like Western States–can also dampen perceived exertion. If it’s special, it’s different. And easier.
  • Variability. A major factor in perceived stress is monotony. Conventional road and track running has far more mental and physical monotony. The latter tends to facilitate joint and muscle mechanoreceptor activity sooner, and more intensely, signaling the brain that the run is more stressful. Conversely, the highly variable terrain of a trail run often seems less physically taxing, while it often (due to technicality or vertical) is more straining on tissues.
  • Addiction Behavior. For better or worse, trail ultrarunning is a draw to addictive personalities. While the long, slow runs through nature are therapeutic, the extremes of time and distance can be a form of self-medication. Addictive personalities have significant difficulty finding and maintaining moderation in both volume and intensity, making RPE a poor choice for this population.
  • Illusory Superiority. There is a tendency for individuals to believe they are ‘above average.’ This concept, called illusory superiority, while psychologically helpful, makes our own perceptions of ourselves a particularly poor metric of physiological reality. As such, we tend to think that either things are easier or harder than they really are. When self-assessing effort, we tend to:
    • Rate an low-to-moderate effort is easier than it actually is (judge a 140 beats-per-minute run as a 2/10 rather than a 4/10)
    • Rate a moderate-to-high effort as more difficult than it actually is (judge a 170 beats-per-minute run as an 9/10 rather than a 7/10)

This is evidenced in research on RPE versus heart rate in highest-intensity exercise, where subjects frequently rates themselves as working significantly harder than their actual physiological measures.

The take-home point is that individuals are poor judges of their own efforts and abilities, and this is magnified in trail ultrarunning where myriad factors dampen perceived intensity. Indeed, this may be why trail ultrarunners have a significantly higher incidence of burnout and overtraining syndrome.

The difficulty in assessing training and racing effort is a compelling argument for the utilization of a skilled ultrarunning coach. However, when coaches fail to employ a reliable metric for effort beyond RPE, not only may they fail to prevent the injury and burnout, they may unknowingly promote it.

A Coach’s Inconvenient Truth

As coaches, it is our goal that our clients run fast and far. Our livelihoods depend on it. So anytime a factor presents itself that prevents fast running, we coaches wish to eliminate it. When coaches endeavor to use heart-rate-based training, only to find athletes having to run (or even walk) excessively slow, that becomes unacceptable. It must be wrong, they think, as it makes no sense why a runner cannot complete their usual six miler in 50 minutes, because their heartrate is 20 beats higher than usual.

But to outright dismiss heart-rate data and go purely based on ‘feel’ or ‘usual pace’ is to potentially thrust their athlete into an entirely different training zone than desired. Additional variables–often measurable only through heart rate–can potentially transform an easy recovery run into a progression tempo run!

And when an athlete is performing an entirely different workout than desired, there are several implications:

  • The coach and athlete can no longer accurately determine cause and effect from their prescribed workouts. This is because these workouts were not completed as intended. Clients ‘running easy’–at times of difficult-to-measure personal and environmental stress–might actually be running threshold pace. And ‘high-end aerobic pace’ might actually be VO2Max pace.
  • A failure to differentiate between types of running efforts negates the value of having a coach. If a coach, in executing a training system, fails to precisely apply and measure aspects of the system, he or she then has no idea if their system is responsible for a runner’s success, if and when they are successful, or conversely, if their system–and not the individual runner–is responsible for a client’s failure.

So now what? If the myriad factors impacting heart rate all count in fitness development, then how do we balance it all?

Tips for Navigating Heart-Rate Training

Heart-rate training has its difficulties, and it is too easy to become psyched out in a closed-loop cycle of ‘negative information, negative mood.’ For tips on how to deal with these and other issues, refer to this resource. Here are some other tips:

Get tested.
To find optimal zones, get your exercise physiology tested in a professional, clinical setting. University research facilities are most trusted, as they use their equipment frequently to conduct research, using well-trained staff. Your next-best choice is a private center that specializes in metabolic testing. While most folks are hung up on VO2Max (the amount of oxygen the body is capable of processing), what is of more importance is:

  • Easy aerobic zone (a zone of high fat burning)
  • Maximum aerobic zone (the zone just before fat metabolism declines precipitously)
  • Lactate threshold

Armed with these correlated zones, you now have a most precise heart-rate ranges with which to work. Some testing facilities will also correlate these zones to treadmill paces. However, this has poor application to the trail ultrarunner who seldom runs on flat, windless treadmills. A heart-rate zone is ‘portable’ for whatever terrain, elevation, and environment you run.

Accept that non-running factors impact physiological cost.
Once you and your coach accept that it all counts, then you’ll recognize the importance in addressing non-running factors. Running and life are not separate containers. What happens in life invariably impacts running. Addressing and balancing life factors such as stress, sleep, nutrition, and environment (temperature, humidity, allergens) will keep their impact on physiology and heart rate minimized, thereby optimizing fitness.

Objectively measure fitness gains.
Fitness does not mean faster. Any runner can train to do more simply by learning to push harder. Pushing harder is not fitness–it is extraction. Fitness is one of two things:

  • Higher performance with the same effort
  • The same performance with less effort

The only way to track true fitness gains is by having a metric. Heart rate is the most useful and easiest metric to track true fitness gains, wherein running faster per heart rate, or running the same easy pace at a lower heart rate equates to true fitness gains. Otherwise all you may be doing is learning to push yourself harder, which–while crucial to peak performance–is an eventual dead end of plateau, injury, and burnout.

Find Ease: ‘The Absence of Hard Does Not Make it Easy!’ and the Endorphin Argument.
This is an oft-quoted line to my clients: that just because a run does not feel hard, does not mean you are training at a low intensity. In fact, if a run feels really good, you may still be running too intensely.

Why do we have endorphins? An evolutionary theory is that endorphins blunt the perceived strain of physical activity, so that we do not stop. When running away from the lion, had we stopped because of pain, we would have been killed, and our genetic material would not be passed on. Those who experienced endorphin release during painful, stressful exercise survived.

Therefore, endorphins may exist to blunt the perceived damage and stress of moderate-to-high intensity effort. This means, in order for endorphins to be released, the brain must perceive the effort to be at least moderately stressful.

Conversely, if your running effort is truly easy, few endorphins will be released! Big buzzkill, but this is a common theme amongst my clients where truly easy runs:

  • Feel extremely effortless
  • Often feel less good than workouts because of the total lack of endorphin release

If you or your coach do not wish to use heart-rate zones, then easy running bouts must feel truly–and unequivocally–easy. They should feel effortless, and at times less comfortable than moderate- or high-intensity workouts.

Listen Closely.
The whole point of a heart-rate monitor is not to restrict our behavior, but to enlighten and educate through biofeedback. But the most superior biofeedback is developing the ability to listen to our bodies. Tune in to its subtle or not-so-subtle messages:

  • Taking full, deep, relaxed breaths, breathing (partially) through your nose is a hallmark of easy, aerobic effort.
  • The presence of absence of ‘effort burn’ in your legs and lungs will help discern between easy and hard.
  • If you find yourself bonking during training runs, this represents a deficit in aerobic effort, or state of being.

Exercise physiology and the science of endurance training can be nauseatingly complicated. But perhaps it can be simplified to a conversation I had with Bruce LaBelle, one of trail ultrarunning’s founding fathers and who is–now four decades later–still out there running in the mountains.

When I asked him about balanced training and the key to running longevity, what he said was, “I train like my dog: he runs hard all day out there with me, and when he comes home, he does nothing but eat, drink, and sleep for a few days, barely moving, until he’s ready to go again.” That’s a funny thing coming from a career research chemist. And, silly as it may seem, this is the philosophy that has allowed LaBelle to continue to run the ultradistances–and continue to get into the mountains on the regular–into his sixth decade.

Perhaps it is that simple: listen to your body. But the demands of a runner’s life and those other things that tug at our heart strings can sure make that difficult. The heart-rate monitor is merely a tool to tune in: not just to the run, but to the totality of our lives.

Call for Comments (from Meghan)

  • Do you train with a heart-rate monitor according to certain zones?
  • How often do you find yourself successfully running by ‘feel?’
  • Can you ever feel the effects of non-running stress on your body when you are out training?
Joe Uhan

is a physical therapist, coach, and ultrarunner in Eugene, Oregon. He is a Minnesota native and has been a competitive runner for over 20 years. He has a Master's Degree in Kinesiology, a Doctorate in Physical Therapy, and is a USATF Level II Certified Coach. Joe ran his first ultra at Autumn Leaves 50 Mile in October 2010, was 4th place at the 2015 USATF 100K Trail Championships (and 3rd in 2012), second at the 2014 Waldo 100K, and finished M9 at the 2012 Western States 100. Joe owns and operates Uhan Performance Physiotherapy in Eugene, Oregon, and offers online coaching and running analysis at

There are 11 comments

  1. Steve Pero

    I’ve been training by HR for 14 years after discovering the Maffetone Method. The main thing I enjoy about training this way is after 20 years of hard training by feel, this is so enjoyable. You can’t train with anyone else, though, otherwise you’re running their HR!
    It works especially well for events like Hardrock and if I am planning on running a shorter road race, I’ll just throw in a tempo run every week.
    I do find it best to find your MHR, then work off of zones. 80% for tempos. A good book on this type of training is Stu Mittleman’s “Slow Burn”.
    If I run by feel for a number of days in a row, I always get run down and return to HR.
    Thanks for a really well written article!

  2. Steve Pero

    The above sentence was altered, here is what I meant to write. I think the greater than and lesser than symbols did something. ;-)

    I do find it best to find your MHR, then work off of zones. Lower than 70% for easy training, greater than 80% for tempos.

  3. Frederic Bard

    Good article.
    I’ve trained with HR since I started running and despite what people/coaches say about the flaws of HR, it is still a very valuable data to have even for trail running where terrain and conditions are very uneven.
    The next useful training data I have in mind would be power and it seems it is coming our way.

    1. OOJ

      Thanks for the comment, Frederic.

      I don’t know much about power meters or measures, but from the sounds of it, it will *only* factor in power (muscle/metabolic) output. If you’re fighting of fatigue, stress, allergies, a power measure would presumably not factor in the energy expenditure in “surviving” these other stressors…no?

      1. Robert

        Power will likely play a prominent role, along with HR, in the future of training for running. The current crop of running power meters appear to be doing a reasonable job at estimating power output (e.g. Stryd), and running power is something that is not affected by terrain, like pace is. Therefore power will be a more sound metric for training guidance, particularly in trail and mountain running with the associated high variance in grade/pace.

        As far as data to indicate the presence of “other”, non-training stressors, aerobic decoupling will be a good parameter to monitor with a power meter. Here is a brief summary by Friel:

        So even with accurate running power meters the importance of HR data will not go away, just as it has not gone away for cycling training where power meters are the central tool for training.

      2. Frederic Bard


        For sure, it only factors the power output and like any technology we can’t rely 100% on it as there are a multitude of factors affecting one’s performance, but I envision that combined with heart rate data and pace, we could come up with a good *framework* of tools and data in order to train more efficiently. The more data the merrier :-)
        I feel like people look for a perfect tool to use while I prefer to see all those tools as guides. Like when it comes to nutrition, there is no *truth* but more a guideline and general rules.

        As Robert underlines well, aerobic decoupling along with other indicators such as Efficiency Index, endurance index..etc will help us guide our training. And to determine those indices, we need tools such as HR belts and power meters along with software to exploit all that (see my article here :


  4. Maria

    Excellent, excellent article. I know a lot of people who run and rock climb. Any thoughts/speculation on how climbing (or I suppose, any activity that requires bursts of power, high HR, and is mentally taxing) might affect running performance? Should one avoid such activities if the priority is aerobic efficiency training for a key race? Or is it ok to climb in bucolic settings where the RPE is low? : )

    1. Mike Tebbutt

      I don’t climb much anymore, but it was my primary sport for a couple of years, and though I never wore an HR monitor, I can confidentially say my HR rarely left the aerobic zone. Same thing in biking and many other sport/activities. Nothing gets the HR going quite like running…

    2. Romanair

      I’d say the relevancy of the cardivascular system demands of rock climing on running perforance is close to none. However other factors like weight gain through muscle mass is a more central issue and resulting in higher energy demands.
      Besides, in my experience it is the other way around. Running has a bigger impact on climbing performance because the endurance training robs you explosive power, which I notice in bouldering.
      Every sportive activity is a form of stress and thus impacts your perforance if it’s not in a kind of active regeneration kind of manner.
      But if you ask me, don’t fixate on such marginally impacts as long as you don’t want to run professionally ’cause you’ll miss lots of fun!

    3. OOJ

      Climbing is no different than any other life activity – how much does that activity impact your running training? Usually, this will show up *the next day* in the run: if you climbed intensely the day before — incurring any systemic stress (be it muscular, metabolic or nervous system) — it will invariably show up in the HR in the subsequent run.

      So like anything else, one must strike a balance between running and Life, and be sure to factor in all our activities as they all dip into that physiological well!

  5. Jacob Rydman

    I’ve heard Mark Wetmore is a big proponent of using HR data to assess the current fitness levels of his athletes and to determine whether they are sufficiently recovering or not. He may know a thing or two about *consistently* and *sustainably* developing Olympic-caliber athletes:) Also, no harm in combining RPE and HR data on occasion to see if perception and reality are lining up.

  6. doug k

    wonderful writing, thank you Joe. HR is one of the tools we have, and it can be very useful. It’s not a single governing principle though, as the Maffetone theory would suggest – that is an oversimplification.

    I trained for a year or so using a HR and following the Maffetone principles. My pace at threshold increased steadily, from 8:20 miles to 10-minute miles, when I stopped the experiment. This was mostly road running. I found I could consistently predict my HR to within 5 beats, based on RPE. Between those two results I went back to RPE-based training for running at least.

    In the pool I take HR in between sets. There as well, I can predict HR at the end of a set consistently, based on RPE and splits: on slow hard days, typically HR is below 140; on fast days feeling good, typically it hits 160. On the days of below 140, I know now to back off the effort and focus on technique, since hard training will most likely just do damage.

    Maria – “mentally taxing” is certainly a stress and it will count.
    “I train like my dog: he runs hard all day out there with me, and when he comes home, he does nothing but eat, drink, and sleep for a few days, barely moving, until he’s ready to go again.”
    One of the basics of hunting dog training is that on the days you work on skills, the need for running the dog is much reduced. It takes them just as much energy to learn and practice, as to run around in circles barking madly.. in fact the restraint on their natural love of running around barking madly, costs too ;-)

    Unfortunately my dog recovers much faster than I do, can’t run hard enough to keep him tired. In hunting season I’ll walk 10-12 miles, he will do 20-30 miles of running around, then he’s nicely tired by the end of the day ;-)

  7. Alison Naney

    Thank you for this (and every column)! As a coach and massage therapist, I’m constantly asking clients what else is going on in their lives and explaining how the body reacts to stress, whether it’s running or a new job, friend, house, etc. Now I’ll give everyone this article. While I think it’s important to run by feel, the only way to know, is to have the realtime feedback of how hard your body is working.

  8. Becca

    Any recommendations for a good HR monitor? I kind of hate GPS, so none of that. I have a Polar with a chest strap, and it is super inaccurate due to loads of electrical interference near me. Thanks!

    1. alicia

      I have a Garmin Charge HR (no GPS) that I love. It was super cheap in comparison to most other HR monitors but it works the best out of all the ones I’ve ever tried. When you first take it out of the box the strap looks like it will be really uncomfortable, but give it a try, it’s actually fine when you’re wearing it.

    2. OOJ

      I’ve had good luck with Suunto, but my experience is limited.

      I’m VERY interested in the new developments in wrist (optical sensor) monitors, as they’re far less cumbersome than a “constrictive band”!

  9. Brendan

    Hi Joe,

    Thanks for the great article. In terms of application to training, can you please recommend any articles or books in terms of structuring ultra training to HR zones?

    For instance, should all but a few runs be done at the aerobic level, etc, how best to structure training to maximise the results, particularly when we are all getting so time poor with other issues in our life (family, work).

    Any help appreciated.

  10. Romanair

    Very well written article and I agree with most of it.
    However, I think you overstate the impact of activation level on energy expenditure.
    I refer to:
    “This means that your eight-minute pace at 160 heart rate–adversely impacted by the environment, anxiety and stress–has very nearly the same cost as your 6:30 pace at 160 heart rate under ideal conditions.”
    In my understanding, the energy demand dictates the energy production. And the energy demand is mainly dictated by the mechanical work of the muscles and all the side processes needed for that level of power output.
    I agree, that the excitation level directly impacts the chosen energy supply system but as long as this system doesn’t actively provide energy, it’s maintaing cost will be relatively low.
    Yes, a higher activation will have a higher energy demand but I don’t believe it’ll come anywhere close to exceeded mechanical enegry demands. But I might be wrong and I’d happly change my mind if your statements are actually based on research…

    1. OOJ

      I think you’re right – the cost isn’t the same (160hr at 6:00/mile stress-free vs 160hr at 8:00/mile with X stress). However, there IS a cost.

      A good example for me is doing a mountain climb. I have a peak I run that is 5.5 miles and +3300′.

      Scenario A: 60min climb, 40min descent, HR 150 (good conditions)
      Scenario B: 60min climb, 40min descent, HR 165 (high pollen count)

      Scenario B results in SIGNIFICANTLY MORE muscle soreness and strain, though the “same power” was exerted. I theorize the difference in energy system (and resultant chemical strain on tissue) is the explain this difference.

      It can be subtle, but there is a cost.

  11. cbs runner

    Some interesting anecdotes from my training and racing that relate to heart rate. I tended to be the type of runner who subscribed to the “no pain no gain” training philosophy until I switched to a Maff like plan three years ago. This switch made my training much less intense (almost painfully so), but I found that at the ultra distance my performance skyrocketed on race day. I am now adding more intensity to try to get to another level, but I seem to be backsliding this year.

    One particular race exemplifies Joe’s comments on outside stress “counting.” I am typically a runner who plans every detail of my races, from nutrition plans and pace charts to drop bags. Everythng is pre-planned. This planning helps me deal with pre-race anxiety; it makes me feel I am in control when facing the unknowns that might (always) surface in a long ultra, but this attention to the race details does not come without cost. It is stress driven. The more I focus on the race beforehand, the more stress I am enduring. Two years ago, I jumped into a 50k the morning of the race. The night before I was enjoying an IPA and steak and had planned on going on a long run the next day. I saw the race had openings and just jumped in. I had no plan at all. Just show up and run. While standing on the starting line, I looked down at my watch and saw my pulse was 40. I remember chuckling to myself when seeing that number. I went on to have the best race I have ever had at 50k. It seemed like a magical day.

    I certainly cannot prove that the low pre-race stress “caused” my success that day, but I am pretty sure it had something to do with it.

  12. Kathee

    I switched to HR training when I read the book “Primal Athlete”. I had just taken a month off running and I was tired of not getting any better and feeling crappy. HR training is slow. Some days slower then others. Stress, heat and hydration really affect my HR. But I feel excited and fantastic about running! I started in February and hoping for an excellent base when I get to August to start my marathon training.

  13. OOJ

    To All:

    Thanks for the great comments!

    Big picture:

    – One does not have to train with a HRM. The point instead is to be able to listen to the body to the fullest, and HRM represents one basic way.
    – HRM training has its flaws and challenges, but it seems to be the best biometric we’ve got
    – The key is to recognize that we have one “bucket” from which we live. And it is a mistake to separate Running from Life.


    Those who can artfully balance Running and Life get the best from both!

    Good luck!

  14. Justin

    The last comment states the point is to be able to listen to the body. I fully agree. Yet I think further, to the author’s point, is that it is truly an inconvenient truth that you can effectively listen to your body to the effect that needs to be done.

    I was reminded of that this morning while running with my HRM. I was tired, tired, tired, and dragging, and felt lame — yet my pace was over 40 seconds per mile faster than it was on Tuesday when I was also using the HRM and I felt well rested and chipper. Tuesday I would have run faster by feel and burnt out, and today I would have slogged a worthless junk run if it weren’t for my little Garmin wrist coach telling me what to do.

  15. D Lip

    Good Article Joe. Yes my HRM pings higher when I drinking Murphy’s Irish Stout, then when someone hands me a Bud Light after a race. Now that’s valuable-and believe me-it all counts!

  16. JDan

    A few years ago I was coaching a UK 100k (road) champion who had a strong tendency to over-train. This runner also had many years background in Biathlon (XC Skiing) so their aerobic base was massive. A problem we discovered using a HRM to control recovery runs after extreme efforts was that if severely fatigued this athlete’s HR would actually stay low, breathing would stay controlled too, but the fatigue and muscle soreness elsewhere resulted in a very high perceived effort, and this athlete could not recover properly despite the low HR reading. To get real recovery we had to really drop the perceived effort massively as well and rest properly. I have a suspicion that for extremely high level endurance runners with a big aerobic background this is fairly common, and probably a major cause of eventual burn-out despite the apparent precautions we try to take. I would add that this athlete (since retired) has not had any apparent heart problems before, during or since.

  17. Jared Friesen

    Excellent article! I personally use MAF training, at least for the past 6 months or so, and have seen great progress using this HR method. After years of saying HR training was not important after using it myself and doing more reading and research I think it is very important and this article articulates that point well. Are you pushing yourself more or actually getting in better shape? Without HR data I am not sure how you could determine this. I also think those folks that use HR data suffer from less injuries and over training, at least in the circles I run in.

Post Your Thoughts