Listen To Your Heart: Tips for Navigating Heart-Rate Training

Stay the CourseRunning has several metrics for improvement. The clock, the track oval, mile marker, GPS watch, and even the bathroom scale are frequently used as measuring sticks for fitness and health. But how do we know if our bodies are positively adapting to our run training, and doing so with decreased stress and enhanced health?

As a runner of 20-plus years and a coach for 15, I have but one reliable tool: the heart-rate monitor. It is all-knowing. Nothing can hide from it.

But using a heart-rate monitor to guide training has its challenges and pitfalls. After several years–and a lot of trial and error–I present the following concepts, challenges, and tips for using the heart-rate monitor in ultra-trail training and racing.

Watch 1

The author monitoring his effort while on a Central Oregon trail run. All photos: Joe Uhan

Heart Rate and Its Meaning

Since the dawn of exercise-physiology study, heart rate has been known to correlate with overall system output, or response to activity. The harder we work, the faster our hearts beat. It is our best measure of how hard the system is working to produce energy and, simply put, keep us alive. And like the stopwatch or mile marker, heart rate can be used as a measuring stick of energy output and performance.

But unlike the watch, heart rate takes into account a third dimension: stress. Since the body and the heart must also adapt to non-running stress, our lifestyle off the trail–work, family, sleep, nutrition–becomes an input affecting heart-rate output.

Moreover, heart rate also factors in external variables like heat, humidity, and altitude. The heart beats harder and faster in adverse conditions.

In short, heart rate is an extension of the Central Governor, factoring in everything going on with our bodies inside and out to determine how to best keep us going!

This is what makes heart-rate monitoring so interesting. And, at times, painfully frustrating.

Heart Rate as the Running Coach

Heart-rate data has two primary uses:

  • To ensure one is running easy enough on aerobic (and recovery) runs; and
  • To ensure one is running hard enough in workouts and races.

Without delving too deeply into exercise science, aerobic running is required to enhance fat metabolism and aid recovery, while high-intensity running is crucial for strength development and race-specific adaptation.

Seems pretty simple, so why use a heart-rate monitor? We are creatures of habit. Humans crave routine and consistency, and too often runners unknowingly run neither easy nor hard. Instead we naturally run somewhere in between. Unfortunately, when we spend to much time in this “gray zone,” we don’t get the proper aerobic fat-burning fitness or recovery, and we don’t run hard enough to maximize strength.

The heart-rate monitor thus becomes a de-facto coach that instills discipline on both ends of the training spectrum.

Heart Rate as the Measuring Stick of True Fitness

People love running because, unlike most other sports, if you work hard, you invariably improve. This is the quintessential training response: run long and hard, and the body will adapt to run a little longer and faster the next time.

However, it is easy to take advantage of, if not abuse, that adaptation, for adaptation does not necessarily equate to enhanced health. Indeed, the body will adapt to even the harshest, most unhealthy habits (like smoking), but that does not mean such adaptations lead to good health.

So how, then, does a runner know she or he is enhancing fitness and health?

In response to this question, and seeking to find the path toward holistic health, endurance-fitness gurus such as Phil Maffetone have for decades been advocating heart rate as the most reliable metric for fitness development, and his Maffetone 180 Formula Method and others are gaining a greater foothold in ultra-endurance training, for good reason: heart rate represents the best measuring stick of true fitness improvement.

It’s simple: running faster at the same heart rate or running the same pace at a lower heart rate equates to greater fitness. It is efficiency defined. The body does more with less.

Without a heart-rate measure, there’s no saying why we run faster. Are we becoming more metabolically or mechanically efficient, or are we simply pushing our bodies harder and farther?

The Challenges and Pitfalls of Heart-Rate Training

So it’s settled, then. We should monitor heart rate, stay in our zones, and we will all eventually rise to max-fitness utopia, right? It’s not that easy. I’ve been a proponent of heart-rate training for several years. I advocate and actively use heart-rate training personally and as an ultra-endurance coach without exception. It’s been invaluable for my and my clients’ training, but it has its challenges.

Heart-rate training is a major paradigm shift. Runners are creatures of habit with deeply-entrenched belief systems. Even if they buy into the theory, it can be a shock when the heart rate hits their prescribed ceiling and they’re a good one, two, or even three minutes per mile slower than their “easy pace.” Heart-rate training requires buy-in and a letting go of often long-held notions of what it means to run easy, medium, and even hard paces. The playbook is rewritten.

If your life is out of balance, there is nowhere to hide. Because heart rate is an extension of the Governor, if the non-running side of life is strained–too much work, not enough sleep, poor nutrition–it will show up in the heart rate and you will have to slow down. Type-A runners used to running their clockwork pace are in for a major shock, especially when (often due to fast-rushing stress hormones!) they “feel just fine,” only to see the monitor hit the roof at the slowest shuffle.

What does it mean? Are these variances dismissible? Several prominent coaches will downplay or dismiss these “spikes” as being irrelevant to the actual physiology. But I disagree. The body predetermines energy selection holistically. So if you’re stressed out, it’s going to push you to anaerobic (to access that fast-burning sugar fuel) at a much slower pace than if the other systems are restful, simply because the system thinks you need that energy system!

Heart rate doesn’t care how pretty the trail is or your level of stoke. Beyond the internal, heart rate is highly sensitive to the environment. Heat, humidity, and altitude are major inputs to the system as are the demands of elevation and tread. This is a huge issue for trail runners, who will stress their system much harder, for much longer, on a beautiful trail among friends than they would on a flat, neighborhood bike path.

But the system doesn’t care. It perceives a great challenge, and will rev the system to deal with it. As such, the metabolic cost of a “medium four-hour trail run” may be similar to a road-marathon race of the same duration. While the muscle stress may be less on the trail, the internal stresses–including the neurological and immune system–may be entirely anaerobic.

Watch 2

It’s not uncommon when excited and amidst great beauty to log heart-rate values such as these, yet claim the effort “feels easy.” This is commonplace at events such as Western States, which features a four-mile mountain climb at altitude at the race’s onset.

While the brain may not register that pain, heart rate does.

Heart rate doesn’t care about the fun group you’re running with and the great conversation. The true gift of running is sharing it with others, and often in a group we will roll along at a strong pace, the conversation flowing, with nary a care about the effort. Indeed, the distraction from the effort is a big reason that we run in groups.

But while our consciousness might be distracted, our heart rate isn’t missing anything. Hard running is hard running and often, when we’re chatting away, our breathing becomes compromised–or we get worked up about an issue–and the system might get revved even higher. As such, many adherents of heart-rate training have to curtail their group running to either run with slower runners or alone. And because many of us run in order to socialize, this can have tremendous consequences.

Being anxious about your heart rate and pace… only makes heart rate and pace worse! So let’s say, despite all that buzz kill, you’re still committed to heart-rate discipline. You dutifully strap the monitor to your chest. Each day you ease into your running, hoping that “today’s the day” you will run fast with a low heart rate. But it never happens, does it? You check your wrist. Every. Ten. Seconds. But today? You’re even slower! The result: you get angry. Anxious. You question. “Am I running too fast? Sick? Tired? Weak? Just a terrible runner?” But anxiety begets a higher heart rate!

And so it goes, the anxious runner gets stuck in the “slow pace, high-heart-rate vortex.”

Finding Compromise: Balancing Holistic Fitness with Running Enjoyment

Heart-rate training is a tough taskmaster. It is a brutally cold, depressing Santa Claus. It sees you when you’re sleeping, it knows when you’re awake (or stressed, or eating poorly), and it darn well knows if your training has been bad or good. But there is a way to use this powerful tool without being beaten down. Here are some tips for striking a balance:

Commit to at least two to three months to rewrite the system. Heart-rate training takes a true commitment, and if you’re new to it, taking a new approach, or coming back from burnout or injury, it will be a significant change.

Find your heart-rate zone and stick to it for two to three months, akin to “base-building.” Do whatever it takes to stick to that heart rate no matter how painfully slow it may be. Within a few days, you’ll get a good idea of what this foundational pace is. Accept it, check the ego at the door, and commit to that effort for at least two months. It will take at least that long to “re-wire the system” and to begin to see real improvements in fitness.

Meanwhile, commit to addressing the other aspects of your life: family and work balance, relationships, sleep, and nutrition. These variables weigh heavily in your training response. Fast, sustainable running depends on finding true balance.

If properly executed, within several weeks you’ll see distinct improvement in your pace at a given heart rate. For example, one of my clients, whose marathon PR was 3:05–but who was hampered with chronic injury–had to initially slow to 10:30-minute miles. But within three months, he was running sub-nine-minute pace. And two years later, his pace–at that same heart rate–is now close to eight-flat pace or faster, with several ultra finishes and a recent equaling of his marathon PR.

Figure what what true aerobic pace feels like. We all have a notion of what easy pace is, but it is often arbitrary and, in many cases, wishful thinking. “If I run everything a little faster, eventually it will feel easier.” Unfortunately, this seldom leads to sustainable fitness gains–thus the heart-rate approach. Once you commit to a maximum-aerobic heart rate, learn what true easy feels like.

What I tell my coaching clients is, easy, max-aerobic pace should feel like “all-day pace,” akin to 100-mile race pace. It is a pace that–at least in the initial stages of heart-rate training–should feel absolutely effortless. In time, your body and brain will truly learn what easy pace feels like rather than the arbitrary grinding base pace previously run. Your previous “easy runs” will now feel like a grind–as they should!

Find and mind your hard-work paces. Depending on your training goals, the next phase of training might include anaerobic threshold and/or higher-intensity, VO2Max intervals. There are myriad resources out there to help determine these paces, including percent-max-heart-rate zones. I like to use an adaptation of the Maffetone calculation:

Max Aerobic: 180 Minus Age
Anaerobic Threshold: 200 Minus Age
VO2Max Pace: 210 Minus Age

While these values (and training strategies) are highly debatable, once you have a set point, stick to these zones in your workouts. These zones will serve as a governor and anchoring point. Then, when your training performances improve, you will know you are training sustainably. Stagnation or regression of paces-per-heart rate (at similar conditions) is a sure sign you are overreaching.

Once you know your easy, “turn away” from the monitor and run by feel! After a few months of disciplined heart-rate training, you will learn your true aerobic pace. If you’ve ever been caught in the anxiety vortex, it’s now time to turn off the monitor and just run! Run easy, be relaxed, run joyful, but above all, be honest with yourself! Run EASY. Check heart rate sparingly if at all, and only make a note of it at the end of the run. Frequently runners will report they will run faster at an equal heart rate simply because they quit worrying about it and just ran!

So long as you’re running close to your zone, you’ll be getting all the training benefits anxiety-free!

Run with a group as your threshold run! For more than one runner I’ve coached, the breaking point of heart-rate training is the loss of camaraderie from avoiding the quick-footed running group. Once base phase and injury rehab goals have been met, go back to the group, but recognize that these runs are now workouts!

If the weekly group run is six to 10 miles, consider doing five to 10 minutes of slow warm-up at your aerobic pace prior to starting with the group. Then grind and chatter away, occasionally checking the monitor to be sure you’re staying within threshold. The next day, be sure to take a slow recovery day.

Be patient, and your fitness will sustainably grow and surpass your former self. Maintain your commitment to keeping the majority of your miles truly easy. Run hard-but-disciplined workouts, and monitor your results to be sure you’re progressing with the same or lesser heart rate. In time, your easy (and workout) pace will progress, until it equals and then surpasses your previous self. And with any luck, you will find yourself breaking beyond previous training and performance plateaus to new heights.

Final Thoughts

True aerobic, heart-rated-based training isn’t for the faint of heart. (Pun intended.) It is hard work, requiring great patience and discipline. But for those interested in peak performance and sustainable, life-long running who commit to the process, the payoff is tremendous: bigger miles, faster recovery, next-to-no injuries, and peak performance with fewer problems. My hope is that these tips will help you navigate the challenges of heart-rate training and keep you committed to the type of training that will keep you running long for a long time to come!

Call for Comments (from Meghan)?

  • Do you run with a heart-rate monitor? When did you start doing so and for how long have you trained this way?
  • For those who started heart-rate training after running “by feel,” what did you learn about your previous paces and how did your paces change for your various heart-rate zones?
  • If you have used heart-rate training for a lengthy period of time, how have you observed your heart rate change in reference to your training and other life factors like work, family, and aging?
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 49 comments

  1. deanger

    As an experiment of one – and with one pair of eyes with which I view my friends – I've noticed the following:

    People who ran in high school/college or were very active hikers benefit a great deal from MAF.

    And people who didn't run in high school/college and weren't very active in weight bearing sports do NOT benefit nearly as much from MAF. Or solely MAF-focused training.

    I believe this is for the rather obvious reason that MAF work doesn't necessarily teach a body to improve things like muscle recruitment, strength, extension, etc… And for slow people (like me) those are by far the greatest limiter. If I trained only with MAF I bet I would still have a MAF of 11:15 per mile. By ditching MAF for hills, fartlek, strides, and plenty of MAF friendly long runs, I've shaved more than 2 minutes off that – (told you I was slow) after having all but plateaued.

    To be fair, I believe Maffetone advocates switching to speed work for a few weeks when MAF stops working, and then switch back when your speed work seems to stop working (that's not exactly right – but he does advocate mixing it up). But when I read the success of amazing athletes like Larissa Dannis who has watched her MAF speeds tumble and tumble with no speedwork — I know that's not what I need to become a faster, more efficient runner. I need strides and hills to improve my MAF heart rate.

    1. 00joeuhan

      Thanks for the comment!

      I agree 1000%. MAF – or heart rate disciplined training, in general – serves to be sure you're truly addressing:

      – aerobic fitness (true fat-burning metabolism)
      – ensuring adequate recovery

      And yes, you CAN gradually develop the "strength" you described, but after a "MAF Phase", runners will benefit most from a Hard-Easy approach…….but the point is, you MUST have the Easy!!

      Your example, Larisa Dannis, is a good one: while she did a TON of MAF work, what propelled her to stardom in ultrarunning was the HARD running she did, atop that base fitness!

    2. CBSrunner

      Well, add me to your experiment of one. I ran in high school and college and later in life continued to run somewhat competitively. Most of my training runs were the gray zone or above, rarely working on my aerobic base. I lived by the motto train harder to get faster. Hill repeats, track workouts, tempo runs were my staples. Cross training was high intensity spinning. Almost every run was near lactate threshold or far above it (unless it was very very long). This made be an o.k. runner at distances up to half marathon, but when I ran longer (marathon and 50k), I suffered from major GI issues from an unknown cause. The nausea I got in longer events was so debilitating that I nearly quit running altogether.

      After years of experimenting without success with minor tweaks to my diet (historically a very high carb diet to sustain all the fast running I was doing) , at the beginning of 2014 I finally decided to totally change my daily diet and also my training regimen. I switched to a high fat diet, bought a heart rate monitor, and began running at a much lower heart rate. Note: The actual MAF formula (180 minus age plus/minus adjustments) did not work for me due to the fact that my MAX heart rate is only 160, quite low for a 44 year old. Nonetheless, through trial and error (and then a Metabolic Efficiency Test to assess my Respiratory Exchange Ratio at slowly increasing heart rates) I found a rate that was so aerobic that I was burning almost entirely fat. I no longer needed to eat as much (or anything) on my long runs and my nausea was reduced substantially.

      Since running ultras involves very little speed (at least compared to my earlier 5-6 minute mile racing days), after only 6 weeks on this regimen, I was able to improve my performance at 50k (Orcas Island) by 20 minutes from the year before. In April 2014, after 3 months of never training above my self imposed low heart rate ceiling (125 bpm), I added one day of hill repeats and a tempo run of 25 minutes each week to see if it would help or hurt my progress. My race performance level saw another boost, and I now began to "race" the 50k distance from the start instead of "managing" the distance to avoid the bonking and nausea I used to feel in the later stages. Oh, and I consumed about half as many calories during these races as I used to.

      I ran my first 100 miler in September, fearing the nausea that plagued me in the past would eventually hit me. Thus, I ran very conservatively for 80 miles (under 110 bpm). The nausea never came, and I finished running my fastest miles to the line.

      So, I am a convert to listening to my heart, but I added in a dietary change to (at least for me) enhance the effect.

  2. borre82

    I really enjoyed reading this article! I have been training and racing long ultras by following MAF.
    Normally I take 3-4 month in the winter, where I only train by MAF, and then I do some strength training and speed work in the fall and summer.

    My “MAF progression” haven’t been as good as some of my training buddies even though I often train more than they do. In some way the 180 formula is a bit too simple in my opinion and don’t take genetic difference into consideration.

    I’m 36 years old and my MAF pulse should then be 149 since I haven’t been injured or sick for a very long time. My max HR is 195 and my resting HR is 48.
    A buddy of mine has the same age and his max HR is 172 and his resting HR is 39.

    He’s obviously much faster at our MAF pulse (fits more to his profile) put I’m faster than him on a marathon where my average pulse equals his MAX HR at 172.
    My average HR for a all out ½-marathon is 182.

    Should I still be training after MAF or should I train after another pulse calculator?
    Been doing MAF training for 2 years now and my minute/km pace has "only" improved by 30 sec at MAF pace.
    I run 4000 km a year.

    1. 00joeuhan

      When Mark Allen – perhaps the famous "MAF athlete" – used this approach, he trained at his aerobic HR until his pace plateaued. THEN he added strength (hills, tempos, thresholds) and high-intensity (intervals, sprints). He found that his MAF then progressed better than if he ONLY ran easy.

      Consider doing more focused hard running, but always come back to your MAF pace for easy/recovery runs!

    2. 00joeuhan

      …ultimately the ONLY true way to determine exact training zones is through a Respiratory Quotient exercise test. Akin to a VO2Max test, it determines what your "fuel mix" is at various HRs. All other methods are simple estimates.

  3. ultrarunnermike


    My PR is actually 3:02 not 3:05, but everything else you say is true. Hard to believe that I couldn't run any faster than 10:30 min/mile at 135 BPM 2 years ago and now I can run 8 min/mile at basically the same heart rate…and I am two years further on the wrong side of the hill. People frequently discount this data as an exaggeration that can't possible be true, but it is.

    My two cents on using this methodology: Strict adherence to MAF will likely NOT result in huge improvements for somebody that is already an accomplished and/or fast runner, or has been in the past. For said athlete, it will probably result in very similar results or slight improvement. The REAL benefit of the process is that it allows you to run at or near your best in a very sustainable and relatively risk free manner. I have had nothing even close to an injury in the two years I have been training at MAF nor have I had any illness, not even a cold…well there is the bout of Norovirus at the Boston marathon last year, but otherwise nothing to speak of.

    I think if your primary running goal is to run a much faster time at a given distance in the short to medium term, then you will likely struggle with MAF training, and you will probably quickly revert to some augmentation to the anaerobic intensive training that has resulted in your past success….Hope you don't get injured, AGAIN. If on the other hand, your primary running goal is to sustainable continue to run well into the future, and time goals are secondary, then MAF is for you.

    My only point is that I think the first hurdle to successful MAF training is to maybe access your bigger goals and motivations. It is definitely not for everybody, but I personally would probably have given up running by now due to all of the addition injuries that I would have otherwise experienced had I not found MAF (and Joe Uhan for that matter).



  4. @SageCanaday

    I would be cautious of religiously following any [(arbitrary number)- age] "zone" formula. From athletes we coach to my personal experience (and spending way too much time on Strava) there appears to be a pretty decent variation of Max. Heart rate ranges that are not consistent age at all! Basing all your "zone training" (i.e I would say Strava zones are quite off) or "MAF" tests/progressions are prone to fairly significant error for many IMO.

    Think of your training in separate, different systems:
    1. The Cardiovascular system (heart, lungs, etc.).
    2. The Skeletal muscular system (leg muscles, tendons, bones).

    Both systems get a training effect in lots of workouts, but sometimes one system is challenged more than the other. (i.e. maybe your heart rate is 160 running up a mountain-trail hill at 12-min mile pace…..but it is also 160 doing a tempo run on a flat track at 7-min mile pace. Heart and lungs don't know what activity you are doing…but the legs sure do)!. The first system can be trained hard over and over and continually adapt over years, but the second system often fails from overuse and leads to injury pretty quickly if pushed too fast!

    The great thing about flatter trail/road/track training is being able to find your Lactate Threshold (Tempo run) VELOCITY at a certain pace (same goes with Vo2max VELOCITY). So if you race an all-out, flat 10km in good conditions and run say around 40-min. You have a pretty good idea (based on actual mile splits) what velocity corresponds to an actual heart rate value. Find that number and you are pretty darn close to true lactate threshold (maybe slightly higher as theoretically LT it is a pace you could hold for about 60-min- all out).

    Now you can translate that number onto the trails….doing uphill Tempo runs, doing hill repeats etc. You've dialed into a magical intensity zone of 85-88% of Max Hr (theoretically). You do steep short hill repeats to train leg muscle power (with quick raises in HR and lactate clearance). You do longer, sustained uphill pushes for a cardiovascular stimulus of extended lactate clearance for 20-30min and push the aerobic system). Those are just quick examples.

    The good thing about MAF is it often slows people down on their "easy mileage days" so they can be consistent, build a steady aerobic mileage base, and not get hurt (i.e. skeletal muscular injury). That is all good. But don't be a slave to the numbers though…variety and periodization are still key…..learn to also run by feel and learn to feel an intensity zone like the Lactate Threshold.

    1. @SageCanaday

      after reading some of the comments above (re: MAF). It really comes down to this:

      You have to build an aerobic base with relatively low intensity running before you add higher intensity intervals/workouts. This is so your skeletal muscular system (prone to injury) can adapt along with your cardiovascular system (which gets in shape at a faster race). Consistent (meaning healthy) training is the long-term secret to progression, success and a long career in the sport. It helps to relax on "easy days" and run "slow" but again, if you're never adding in strides, hill workouts, intervals and Tempo runs you're not going to reach your full potential.

      Arthur Lydiard preached this decades ago and any comprehensive training program/coach nowadays should address this.

    2. 00joeuhan

      I respectfully – and wholeheartedly – *disagree* with this statement:

      >The first system can be trained hard over and over and continually adapt over years, but the second system often fails from overuse and leads to injury pretty quickly if pushed too fast!

      One only needs to look at the SCORES of top ultrarunners bogged down – or out – with over-training and burnout to see that the metabolic system *cannot* be pushed over and over. And based on clinical experience, it is the *metabolic system* that creates chemical stress that erodes tissue, creating muscle/tendon/bone injury:

      HRM is crucial for trailrunners to be sure they know how hard their pushing their physiology…simply because it's so much easier on the legs.

      The rest of your commentary is spot-on: optimal training for performance and longevity is dynamic!

  5. dotkaye

    mostly agree with Sage and the Lydiard ideas.

    The big breakthrough for my marathon time was doing long slow training runs with ultramarathoners, so added a truly easy long run 20-30 miles to replace my usual 13-18 miles at marathon pace. That dropped my time from 3:08 to 2:45, then a few minutes more with hard 10k training.

    I tried the MAF method one winter, for 3 months. My MAF pace started at 8:50 miles at 140 HR. After 3 months it was 10:30. I guess I wasn't doing sufficient run volume (triathlete) to make it work. Mark Allen had decades of high-volume high-intensity training behind him, when he started with MAF – and note that on MAF he was still training 15-20 hours a week. Even at easy pace that's a good training load.

    Here's a compare/contrast between Lydiard and Mark Allen's training methods that I wrote up, after reading a 99-page Letsrun thread..
    Mark does not use a pure MAF method but it is quite close to Lydiard, so I'd be happy with either protocol.

    Both systems use a repeated cycle of base/sharpening/specific training. Lydiard had a 6-month cycle allowing for two peaks a year, Mark uses the MAF test to determine when to shift the focus. The MAF test seems very close to Lydiards' "time trials", a test that gives the coach the metric and data to fine-tune training.

    – Base: Lydiard liked 8-12 weeks at a minimum, more is better: Mark mentions 4 months. Lydiard threw the watch away and asked his runners to run at a pace that left them 'pleasantly tired', but feeling able to do more. Mark gives an exact HR range based on Maffetone's numbers. The HR makes a lot of sense for new athletes who don't have a good sense of RPE, and as a reality check for experienced athletes: personally I think the old-fashioned LSD 'talk test' works fine too.
    – sharpening: Lydiard has fairly detailed and specific sections, but he's on record as saying the actual anaerobic sessions don't matter much, as long as the required work is done. Typically about 3 weeks of running economy work, using hill springing and downhill running; followed by 4 weeks of 'anaerobic training', 2 to 4 sessions/week of the basic interval work we all know and love. Before reading the letsrun thread, I had not realized how much drilling/running-economy-specific training was done in the 'hill training' phase.
    Mark is a lot less specific, but the principles are much the same:
    "high end interval anaerobic training one or two days/week… just like the aerobic training, there is a limit to the benefit .. you will see your speed start to slow down again.. signal that it is time to switch back to aerobic.. Keep your interval sessions to around 15-30 minutes of hard high heart rate effort total."
    – race conditioning: Lydiard uses weekly time trials (not race-effort) and short high-intensity intervals, reducing volume but not intensity over the last few weeks.

    The commonalities are a base of pure aerobic training, a training cycle that repeats the basics over a maximum 6-8 weeks of any one phase (except base, where more may well be more), and regular tests at known distances and efforts to measure the results of the training.

    My favorite quote from the letsrun thread:
    "Eventually the Lydiard system vanishes, like the state was supposed to under Communism, and the runner just feels it. It is the way musicians do it. Music and running are really the same thing – performance and emotion."
    Tom Derderian..

  6. deanger

    Slightly off-topic, only slightly – do you all have "gears"?

    For example – I've noticed certain paces feel right – and if I go up or down even 15 seconds per mile the corresponding change in RPE and heart-rate is more dramatic than I expect. Over time, my gears all seem to get slightly faster. But I definitely have gaps in between them where I'm sure I'd be better off a little faster or a little slower (I'm sure this is all about body composition and form, etc.)

    Anyway – this is where high intensity helps me. It seems to bump the gears 10 seconds or so. Then the low intensity gets my body ready for the next stretch of high intensity.

    Oh and one last thing. I will say I'm amazed how much further I can run staying near MAF then even going 10 beats over it. When you're doing it – it doesn't feel like it will matter – but 5 hours in I'm either fresh or dead.

    Great thread

  7. @gen3ticfreak

    HR training in the ultra world or any running discipline involving significant vertical gains makes so much more sense than pace based training. Cyclists have had the ability to monitor their efforts in realtime using power meters for the last decade. The runner's closest realtime effort measure is HR.

    Unfortunately there are caveats to HR based trading such as environmental issues (heat), immune system health, and mental stimulation. I think one should be more holistic than following a prescribed number when it comes to HR training (ex. perceived effort in conjunction with HR)

    I am not a true believer in the MAF calculation. In fact anything that involves using some number minus your age can't really represent what is correct for you. A max HR test will tell you exactly what the zone breakdowns will be and even then those zones can be moved slightly as fitness changes.

    I would say that the improvements at MAF HR have come from improvements in mechanical efficiency and the body's cellular level adaptation. As Sage and others have mentioned more significant improvement can be realized (especially with respect to lactate threshold HR) by adding more intensity but, only when the body has recovered from the previous bout of intensity.

    How do you know when you're recovered? Check out the research on Heart Rate Variability (HRV). Polar, Garmin, and Suunto are all utilizing some form of HRV to estimate recovery based on HRV. There are a few phone apps that will use your Bluetooth based HRM device to determine your readiness for intensity as well.

    1. Andrew

      I use HR for a lot of my training and some during races. I do not Only use the HR data, I also am watching pace and very much going by feel (I think I learned feel from the HR data).

      I have done a handful of runs with the new Stryd power meter/HR strap and finally got to wear it in a 50k this past weekend. The race had about 14,000ft elevation change so for me that meant a good bit of Run/Hike/Run/Hike. Watching the power/pace/heart numbers was actually pretty darn cool. Whatever formula they are using to come up with power felt very dialed in to me. The power number was much more useful than HR later in the race when global fatigue had set in and HR does not respond as well. I am very curious to keep testing this thing out because of a lot of the HR limitations. Including intervals and hill repeats where there is never time for HR to fully respond.

      I have also done the HRV for recovery status testing. For a long period I did it every day when I woke up. It does have a lot of merit, but personally I did not stick with it. I found that I was going to stick to my training regardless of what the reading said. Again, I tended to default back to felt sense. If I felt like doing the workout would cause a problem, I changed it.

      Some recent studies have shown then RHR may be just as, if not more effective than HRV, and that a coach simply asking an athlete how they Felt was more effective than either. Go figure.

      I love data and am a gear nerd. I think most of it is helpful as a teaching aid. We can use it to safely become dialed in to our own intuition and learn our limits. But, I think that a dialed in, trained human mind is far more sophisticated than the external. .. Maybe :)

  8. trailbitch

    I would like to improve my half marathon time in the next 3 months (currently 2:00 is my PB). My easy pace already feels painfully slow but since I haven't made pace improvements in years, I'd consider trying this. I would like to focus more, though, on running for weight loss. Would this help with that goal, or is that another style of training?

    1. 00joeuhan

      Optimal fat-burning metabolism comes best from two types of exercise:

      REALLY easy
      REALLY hard

      The former teaches the body to utilize fat-burning enzymes in muscle cells at the time of exercise, then develops even more for subsequent bouts.

      The latter is high-intensity that drains the system, and burns fat after-the-fact, creating enhanced fat metabolism.

      Runners who "work pretty hard" – yet tend to carry excess weight – quite frequently are working TOO hard, and not doing nearly enough of the low-intensity.

      My recommendations:
      – do 95% of your training at MAF HR
      – do 5% HARD (but no more)
      – "balance" your diet by INCREASING fat intake (especially early in the day) and cut back on carbohydrates.

  9. LightningRacer

    I agree with Sage that HR zones often don't align with the commonly used age formulas. I'm 46, but my training zones and maximum heart rate are similar to what they were in high school. MAF would have suggested ridiculously high zones for me in high school. I actually ran (too) hard workouts at roughly MAF in high school, but it left me terribly overtrained – for instance totally wiped out for 2 weeks after workouts in that zone. It would have been inconceivable to try to run that effort every day. Even now at 46, running at MAF puts me around 6-low mpm pace, which is not what I want to average on a typical run. I go maybe 2 days a week harder than that for a controlled/limited amount of time, try about one or two days a week at around MAF HR (but often fail to be able to go that hard, because it's hard), and about half the week at a HR that ranges from 20 to 30 less than MAF suggests (180-age 5 for fitness adjustment). My easy run today was run at 102 HR, which is MAF minus 37.

    I do use a HR monitor most runs, and I know what HR range I want to use on any particular day, but it has nothing to do with age.

  10. Andy

    I'm no exercise physiologist, but I do wonder what the individual difference predictors are for how effective MAF will be. Will someone with a long history of track and road racing who is used to training at much higher HR benefit more, as compared to those who have been doing mostly — if not only — LSD runs on the trails for years?

    And though MAF and related HR based training may work for many, I seem to recall Karl Meltzer saying years ago that he would run pretty hard on most runs, probably well exceeding optimum aerobic rate based on MAF. As a low-tech option for base training, I recall somebody (Scott Jurek?) suggesting that one way to run truly aerobic on long runs is to breathe only through your nose. If you have to open your mouth you're pushing too hard. I've used this on and off with good result. Pretty scientific, right?

    1. @SageCanaday

      If I ran at MAF at lot (i.e. 145 bpm) I'd probably get injured fairly quickly or be totally overtrained. I usually run my "easy aerobic days" at around 130bpm. The HR numbers are all relative and fairly arbitrary though as it is % of one's individual max HR that matters. More individual variations throw things off even more. But I think the opposite is true of what you wrote…for some who have just started distance running and haven't done a lot of "formal training", maybe in the 30-45 year old age range, MAF might be slightly more accurate (but for sure not for many). So I usually train at a much lower HR and then on harder/interval days my Lactate Threshold is fairly close to half marathon pace (which is almost exactly 12-15/sec per/mile faster than full marathon pace). HR on those days is way, way over MAF (i.e. well over 85% of max) and a Vo2max session is looking at 95%+. But a lot of people (including myself) don't even know their true, 100% max HR (hard to read even in a Vo2max test as it's hard to push absolutely 100% in a lab) and maybe a 2 x 800m all-out time trial with a short rest will get you very close to 100% max HR, but you might pull a muscle and will be swimming in lactic acid (not good for your aerobic development)! Jack Daniels (not the whiskey guy!) has a great idea in his books: use actual, current race performances like 5km, 10km or half marathon road races/track to approximate Vo2max and all intensity zones. From there he charts out "VDOT" values that correspond to velocities at Lactate Threshold, Vo2max, etc. From a recent, all-out 100% race performance you get a pretty accurate idea of how your fitness is at the current moment (taking Running Economy into account too!). A simple, 20-minute "Tempo Run" on a smooth, flat surface in good weather conditions at an even pace with an overall "perceived effort" of around 85% will yield a pretty decent indicator of velocity/pace at Lactate Threshold and possible corresponding HR value that will give you a relative number to base future training/efforts off of.

      But the real trick (the "art" in the "science" of training) is learning to "Feel" your lactate threshold…know how to ride that fine red-line and get the appropriate stimulus. For breathing…easy days should be "conversational pace"…i.e. you can easily carry on a conversation and fluidly speak full sentences….that and/or about a 3-3 breathing pattern (exhale with 3 steps, inhale with 3 steps etc.)

      1. 00joeuhan

        I suppose the true intent of this article is how to use the HRM as a tool – a metric – for your training goals. MAF is a type of training: a way to estimate aerobic running.

        Ultimately, what Sage is suggesting is most important:

        – run truly easy, "all-day pace" — then note what HR that is
        – run threshold, that "pretty hard but doable race pace" — note what that HR is

        Use those HRs as benchmarks to guide training, then use the relative HRs + splits to track fitness!

        TRUE fitness:

        = same pace + lower HR
        = faster pace + same HR

        1. @SageCanaday

          Joe you wrote in your recommendations:

          "My recommendations:
          – do 95% of your training at MAF HR
          – do 5% HARD (but no more)
          – "balance" your diet by INCREASING fat intake (especially early in the day) and cut back on carbohydrates.'

          I'm going to have to disagree with all of those. Again, I think we addressed the flaws with MAF. Doing 95% of training at MAF HR would wreck/injure some. Again, it's about periodization and variety in training. It's not a black and white spectrum of "hard" and "easy"…it's a continuous spectrum with shades of gray…marathon pace, aerboic threshold, Vo2max, anaerobic threshold/Lactate Threshold, anaerobic capacity, alactic speed etc.). Periodization throughout the year will slightly change the emphasis/balance with volume v. intensity (although I as well as many other coaches have found a pretty distinct 80/20 to about 90/10 ratio of easy-aerobic training in relation to training at Lactate Threshold and above intensity in any given week out of a training year/cycle)…and yes i'll count Strides and hill reps/sprints in there as quality work!

          But to suggest to people to eat more fat? I don't want to get deep into the diet debate here, but alas I'm very opinionated! I eat a very high carb (think beans, fruits, veggies and some bread/pasta/pizza….and Beer for carbs) diet and burning fat efficiently as a fuel is never an issue in a marathon/ultra (just like it isn't for the East Africans who eat very high carb) . If anything, i'd suggest people not worry about their intake natural, whole food carbs (but cut-out refined sugar of course!) which is great energy, usually very nutrient dense, and full of healthy fiber. I would also suggest (however delicious it may be) not to blatantly go out of one's way to "Increase Fat Intake". (i.e. Maffetone and the whole butter and oil in coffee thing). I'm sorry, but if you want to run fast and recover fast you need to fuel up with carbs from things like fruits and veggies and beans and rice. Less free radicals, more antioxidants, and chock full of nutrients.

          1. 00joeuhan

            Sage, have you ever, *ever* had a legitimate weight control issue? If not, it may have less to do with your running and "healthy high-carb diet" and your relative genetic insulin sensitivity.

            Conversely, individuals who exercise copiously (e.g. >30-60min/day, as recommended) and eat a traditional high-carb diet as you prescribe, who are clinically (or even marginally) overweight are likely *insulin resistant*: their body stores every bit of extra carbs as fat.

            You are not. I am mildly (but not very) resistant. A TON of runners out there *are* insulin-resistant, which is why they have a tough time losing weight even with huge milage. In fact, many tend to GAIN weight, running the same miles/workouts, as they age.

            In a clinical setting, I have had tremendous success recommending a *balanced diet* of more natural fats (from both plant and animal sources), with an overall carbohydrate reduction, AND with a low-intensity exercise regimen, as a baseline for developing a healthy foundation.

            The HRM approach helps ensure they're not over-doing training. Running in "the Gray Zone" for an injury-prone athlete with poor fat adaptation will drive them toward carbohydrate cravings, and tend to slow both fitness development and weight loss.

            1. @SageCanaday

              Joe, insulin issues often come with a high intake of highly refined carbs (table sugars, high fructose corn syrup, wonderbread bread). I'm not promoting that obviously. Since when did eating more veggies and some raw fruit (a main source of carbs) cause insulin issues and obesity? Consider that eating a steak alone will cause a horrific insulin spike. I'll cite a study supporting that at the end of this comment. I'm just saying (and I realize we are getting way off topic here), I think it is a foolish "balanced diet" if one suggests increasing fat intake. The standard American diet (SAD) is usually around 30-40% fat already. Most Americans get plenty of fat (and refined carbs) already. We're dying of heart disease, stroke, cancer and diabetes and half the population is obese. Of course in the short-term people lose weight on a Paleo/Atkins/whatever diet…but it is not good for long-term health and not sustainable. I'm making the assumption (perhaps falsely) that since you are seemingly in agreement with MAF on heart rate training that you are also (somewhat) inline with his dietary "recommendations?" Maffetone recommends putting butter and oil in one's coffee….do you agree with that as a healthy practice?! Re: insulin spikes see page 10 of the following study:….

            2. CBSrunner

              I might be misreading this study (and it does state that some high protein foods have a higher than expected insulin response) but the graph on the page Sage directed us to is very misleading. It is a graph that essentially represents the insulin response given the glucose in (or converted from) the food. Since beef has very low glucose, the insulin response it generates (as shown in the graph) looks huge. That does not mean beef's insulin response is huge. In fact, it is lower than every piece of fruit tested. Sorry Sage. I just hade to clarify this because I was on a very high (probably too refined) carbohydrate diet for years and upon switching to a higher fat diet (and admittedly eating much less refined sugar and grains) my ability to burn fat in ultras has skyrocketed.

          2. Manu0505

            I think you're being a little unfair here. Just as a high carb diet does not mean all refined carbs, a high-fat diet does not mean no vegetables and no whole foods. In fact, Maffetone is a strong proponent of natural foods and cautions against eating the kind of crap you are associating with such a diet. This is not the Atkins diet we are talking about. There are no limits on natural carbs in many high fat diets and most adherents end up replacing bread with lettuce, kale, etc. and eating a ton of vegetables. Also, you are an elite athlete, devoting a ton of your life to training. Diet matters less to you than it does to the average trail runner. You are fortunate to have the resources and the knowledge to pack yourself with the finest whole foods diet money can buy. Many of our country's finest Olympic athletes are subsisting on garbage diets of fast food and other non-nutritive sustances out of sheer poverty and still wining medals. Just like Bruce Jenner on the box of Wheaties, you could pretty much attribute your running success to anything.
            Also your argument that MAF didn't work for you, and therefore let's dismiss it seems highly unscientific. Part of establishing a successful MAF regiment involves fine tuning your MAF threshold. The formula for establishing your MAF # is just a starting point. To suggest that all adherents to the MAF training philosophy stupidly compute the formula and follow it without any further adjustment is a ridiculous assumption.

  11. deanger

    Can someone explain something to me — some people can run all day at their MAF. Other people (like Sage) that would be too much. Obviously, Sage is in pretty good shape…

    So what is the correlation between MAF and fitness. I mean, I get the basic idea that if 142 gets you 10 minutes a mile and then 6 months later it gets you 9 minutes a mile that's great… But why would MAF for people who are super fit be too fast for slow runs? Is it because of other limiters?

    1. @WoodgateTweets

      I think the fitter you get (Cardio vascular) the faster the pace @MAF therefore the tougher it is on the muscle skeletal system.. someone like Sage would likely be sub 6min smiling at his MAF HR and that is very tough on the body

      1. @SageCanaday

        I have estimated that if following MAF my pace would be very close to 6-min mile or faster on the flats (at sea level, flat surface, good weather). That is way to hard for my skeletal muscular system and lead to injury/overtraining.

        Joe I think implied that my MAF would be "all-day" pace….(as much as I'd like to think that, I know that is not a sustainable pace for me for more than about 5 hours on a track…if even that)

        Individual differences in HR variations (as well as age in training, volume of training, experience, diet all play a role). That's why his formula isn't good to spread around like gospel IMO.

        Again, Arthur Lydiard has preached the aerobic base building idea with easy to moderate intensity running for decades (as have other coaches who delve into actual science like Jack Daniels and Pete Pfitzinger and David E. Marin. It appears that Maffetone just jumped on the "aerobic bandwagon" and then threw in a twist with his Atkins/Paleo like diet recommendations as well as many absurd comments on how easy it's going to be to crack 2 hours in the marathon. You don't need to eat a lot of fat to burn a lot of fat!

        1. deanger


          First of all, thanks for taking so much time on this thread. Between you and Joe and everyone else, there is a lot of good stuff. I always thought overtraining was a cardiovascular issue only, for some reason, when it came to running. Not sure why I had made this assumption which, now that I think of it, doesn't make a ton of sense. For guys like you then – would you say that is the system that ends up being your limiter? (That's the reason you can't run a 1:59 Marathon ;) )

  12. TBowling2

    Thank you Joe! I think this article came at a perfect time for me. I've done four solid months of strict MAF training, but have been talking about adding some hard/fast miles once a week to see some improvements. It would also be nice to run with friends again!

  13. naynaynaynay

    I think that both Joe & Sage would agree to an extent that they are, on a lot of points, in agreement but the scope or angle of their criticisms make it appear as if they are in contention.

    Maffetone suggests fat in coffee. He does not suggest fat in coffee EVERY morning. Sage suggests healthy carbs such as vegetables and fruit. This does not mean he has pasta every night. Not only the content but the portion-size of any prescribed diet ideas ride along a sliding scale (my personal opinion is that most discussions of diet devolve away from nutrition and what takes center stage is the wholly innocent human desire to control reality with fixed values). Maffetone's approach is not for optimum performance, it is for optimum wellbeing. When one reaches a certain level of competition such as Sage, there are certain measurable and intelligent concessions that are made by an athlete that value performance over OPTIMUM wellbeing. People might disagree with this statement because they want to think that they can have it all, a stress-free life AND a podium finish. But no matter the fitness of an athlete, competing at the top level is…STRESSFUL (not like stimulus stressful, like cortisol levels stressful). Um, I should say that I think reaching that level in ultras is totally amazing and awesome. But here, at the high levels of competition is where Maffetone becomes more vague and suggestive as opposed to Sage or Lydiard who strike on, providing tangible strategies. Neither approach – both in exercise and diet – are inferior. *Remember that nutritional recommendations are generalities, given with a lot of faith in us as smart individuals, they are not universal statements. So we might want to say "meh" to eating like a cave man every day, "blah" to eating eggs every day, "huh" to eating fruit every day and take the grey pill of moderation and specification instead. Be reasonable and good to yourself. Enjoy healthy foods, fats, carbs, proteins, The goal of MAF is optimum wellbeing (and sure, you can get reasonably fast too if you do it right) while Lydiard/Canova/Daniels approach is leveraging wellbeing into optimum, exceptional performance.

    Optimum wellbeing. Optimum performance. Eat good food. Enjoy.

    If a mid-packer or back-of-the-packer is not improving using strict MAF (super fit folks who are not improving is a more nuanced situation, as Sage described), then there could be blockages in the individual's lifestyle that are impeding improvement – which is simply great information to acquire. Maybe better sleep, work on the marriage, diet-related stress, road rage etc. It's a wonderful perspective to encourage as it allows for an individual to leverage stress-reduction in facets of life that were otherwise winning out.

  14. Luke_B

    This diet discussion deserves its own separate discussion. When my son was put on a 4:1 ketogenic diet (80% calories from fat, 10% from protein and from carbs) due to a neurological condition I had the opportunity to do a lot of learning about the science of what makes you fat, gives you heart disease, causes fatty livers, etc.

  15. @henhouserunner

    Thanks for another great article, everyone is a gem. Just wondering how you calculate your MAF HR using the Respiratory Quotient that you would get from testing. Like others, think 180-age is too high for me.

    1. CBSrunner

      I too thought the MAF rate was too high. I think MAF is just a very broad generalization, but we are all unique, so applying it like some magic formula is not wise. Calculated MAF for me was 135 bpm or higher (45 years old). That pace was equal to a reasonably hard effort (above my 50k race pace by several beats) and certainly not a pace I could carry on a conversation very well. I decided to use 125 bpm instead.

      Interestingly, after a few weeks of very long slow aerobic training, in January 2014 I had a metabolic efficiency test (MET) done to determine my Respiratory Quotient as effort (heart rate) increased. My crossover point 50/50 fat/carb turned out to be 134. Notably, my estimated max heart (based upon my VO2Max plus a few beats) was 162, so that meant my crossover on that day was 82.7% of my max. From what I have read, that was high. Based upon my perceived exertion during easy long runs, I decided stick with 125 as my max rate for my aerobic training. Most of my runs were at 115 average. A year later I was re-tested and my crossover point was up to 140.

      Based upon the thee MET I have taken over 18 month period while experimenting, I don't think using the MAF formula works well for me at all, but I also don't think lab testing will be perfect either. My numbers seemed to be heavily influenced by my dietary intake in the hours before the test. There are just a lot of variables to control for. Thus, finding the right training zones is part art and part science.

      Note: one plus of the lab testing was that I had a reasonable estimate of what I was burning (fat/carb) at various heart rates. This helped in ultra race planning a lot, as I don't tolerate excessive (unneeded) carb consumption without nausea. I now eat far less per hour and more fats on longer ultras and can mathematically know I will not bonk. That has made me more confident on race day.

      1. @henhouserunner

        Thanks CBSrunner. I am using the talk test (or sing along test if I am alone) and defintely feel the 180 – age is too high so slowing it down although as Joe states not easy when you have a comfortable gear. I would have thought though that the MAF HR migt be lower than the 50/50 crossover.

  16. romanair

    I'm a bit confused with the different threshold concepts and their implications on the heart rate. In my experience, when talking about aerobic or anaerobic thresholds one refers exclusively to the main energy utilization pathways of the working muscles. If I'm not mistaken those thresholds are based on lactic acid levels, which is a byproduct of the anaerobic pathway and an indirect measure of the acid environment of the muscles. When pushing too hard the muscles get overacidified, ultimately inhibiting their function.
    Now what I'm asking myself is, to what extend does the HR reflect that performance limiting phenomenon? And especially what implications do the unexplained HR deviations have on the performance?
    For example in my first 50k I had a HR of ~140bpm befor the race started (probably out of excitement) and ended up with a HR over 170bpm for more than 4h. I once did a a lactate threshold test and they determined my aerob-anaerob threshold at 157bpm. So if the HR would directly reflect the lactate levels it should've been physiologically impossible to run 4h+ with that HR.
    Sure a raised HR is a stress indicator, but is it in that case performance limiting?

    1. @SageCanaday

      Lactate threshold is not a limiting factor in events lasting much more more than about one hour…or about up to a high intensity half marathon…unless it is the Pikes Peak Ascent or something at really high altitude (where you're going to be breathing really hard)!

      So lactate threshold (anaerobic threshold) is usually about 85-88% of Max HR. One can measure blood-lactate concentrations to help plot the threshold (the "lactic acid" comes in in anaerobic metabolism when positively charged Hydrogen comes into to attach to the Lactate and make it acidic). Of course this shuts down aerobic pathways and can even stunt/hurt long-term aerobic enzyme development. Muscle fibers also don't operate well in an acidic environment and you're likely breathing very hard (and in a lot of pain) at this point!

      But i'd question the accuracy of the numbers/reading on your HR monitor and/or your aerob-anaerob threshold test. Actually the 157bmp sounds pretty reasonable (we don't know your age, but it's all relative). However, if that value is true, there is no way you really held over 170bmp for more than 4 hours as likely that would be closer to your Vo2max and Max. HR instead (and again, you can't really hold Lactate Threshold for over an hour because you are getting consumed by lactic acid/lactate build-up).

      And of course Lactate build-up and blood acidity isn't really limiting factor in ultras. Fuel conservation (i.e blood insulin levels, fat burning and glycogen) as well as issues like sheer muscle fatigue (cramping) and dehydration are more specific limiting factors to ultras. Of course charging up a hill and not burning a bunch of carbs or "going anaerobic" is always nice though! So aerobic efficiency counts…even at much sub-maximal paces and nearly all aerobic energy paces (aka fat burning)…that's why we train Lactate Threshold still!

      On our coaching website ( we have a free Pace-Intensity Spectrum Chart that you can download that visually defines the difference between things like "aerobic threshold," "lactate/anaerobic threshold,", "vo2max" etc. as well as corresponding HR values and flat-running pace/intensities. Good luck with your training! Again, HR monitors (as well as some lab tests) can be wacky and prone to error and you can't always trust the numbers they spit out!

      1. romanair

        Thanks for your reply.
        The anaerobic threshold seems to fit quite well with your 85-88% of HRmax forumlar. My actual HRmax deviates more than 10bpm of the 220 – Age formular.
        The threshold test was a couple of years ago so maybe I just got the wrong number in mind.

        My performance limiting question was more aimed at Joe's statement:
        "While the muscle stress may be less on the trail, the internal stresses–including the neurological and immune system–may be entirely anaerobic."
        If stress levels for the muscles are relatively low but your HR is abnormally elevated by internal or phycological stresses, will they strongly influence your running performance or are they neglectable, since the muscles are still the main contributor?
        And does the importance of internal stresses increase with elapsing race time?
        I often observe an updrift in HR and breathing frequency when exceeding a couple of hours and the HR decrease is abnormally slow when stopping. Is that maybe the point where the performance limiting factor of muscle stress is overtaken by stresses on the cardio-vascular, respiratory, neurological and enzymatic systems?

  17. Steve Pero

    I've been running LHR training now for 12 years after coming upon an article written by Phil Maffetone…but over the years have adapted it as I learn. I've been running for 40 years, so know my body pretty well.
    Initially I stuck to my MAF pace and only that…and guess what, running was very easy, but I got slower ;-) I liked this new comfort zone and it worked well for ultrarunning (Hardrock), but i also like running 5K's. So I added in some speedwork in the form of a weekly tempo run. My upper level comfort got better and I did get some speed back, but I am also aging, so need more recovery. Then I read about short sprints to help with the loss of fast twitch as I age and added those back in and needed to take more days off to recover. ( My training probably more follows in line with Hadd, look it up)
    So what's working for me now is I run 4 days a week, 2 days of an hour at around my maf, but throw in some 15 second sprints in the middle. One tempo run, run at 85% of my MHR and one long run run around MAF, but more at a comfort level of the old talk test. I learned to NOT become a slave to the monitor. This magic combination has given me the ability to finish well at 5K's (ran a 22 min this past Summer, slow to some, but I'm 64), yet also run well in ultras by just increasing the long run.
    So in summary, you can make your training be recovering and stressful at the same time…just try it and adapt it to your needs. See you at Hardrock or the local 5K! ;-)

  18. pinerun

    After reading Stu Mittlemans book Slow Burn, I have been aware of some of the training methods discussed here. I have used these as guide lines and am usually running, especially my longer runs, at a slower pace where my heart rate is quite low. Now and then when training for an upcoming event, half or full marathon, I will incorporate some speed work, and expecially hill training which I enjoy more. I am not into crunching numbers andI am not an elite runner my any means, however one interesting side effect from many years of slow training is that my resting, morning, heartrate is at an elite level, 35-40 pbm.

  19. adventureartist

    Hopefully I am throwing in a new question. Here is the background. I used to be coach by Roy Benson, a long time-time researcher and coach of HR training, while Roy has retired, I am using his methods and book to get back in shape after three months off with a broken foot. A little experiment.

    I was tested in a lab and know my max HR. I was using % of MHR, running painfully slow, 3-4 minutes slower than marathon pace and sometimes I just have to walk to keep it down. (no sweating even after 1-2 hours) Then I came across my pace calculation from the lab who did my metabolic, LT, etc. tests. They had very different numbers because they used %HRR.

    So, is it % of HRR or % of MHR to build up that aerobic engine?

  20. @ToddjVogel

    Great article and conversation – thanks! I am confused by (at least) one point,however. To wit: I decided to try the MAF test today and, after warming up, found it challenging to reach my MAF heart rate of 128 – 133 (calculated as 180 – 52 + 5 for good fitness/no issues/meds). Not so much challenged as I was surprised that getting to that heart rate took as much effort as it did. My impression from what Joe wrote was that most runners would need to slow down to be in the appropriate aerobic zone. I ran the three miles and indeed each was slightly slower than the previous but all felt MUCH harder than my usual training pace. During the test I was running just over 8 minute miles whereas my training is more typically 9:30. Admittedly I enjoy running at my all day pace…

    So this left me wondering, have I been training too slow? I think the concept of training as one’s aerobic max makes sense on shorter runs but how should the tactic be used on longer distance (training) runs?

  21. @Lx49

    Another metric to consider is the breath/step ratio, which for me is something like 1 breath per 8 steps (inhale and exhale, both legs counted) easy, 6 moderate and 4 hard. I'm not an ultra runner nor competitive however I find the focus on it brings attention to my center, which I find encourages better body awareness. No batteries required either!

  22. @hrangeapp

    I don't mean to be spammy but I think this is relevant to the post.

    We are developing a fitness app entirely based on heart rate training theory. It's called hRange ( and it's available for iOs. The app is still in development and we are looking for feedback. We'll give the app for free to all testers.
    You can become a beta tester by signing up here:

    Happy Workout :)

  23. Xosé M.

    “check the ego at the door”: main point of all this article.
    It takes patience to be on the “real” aerobic range but on long term you feel better because you “run-far” (and probably faster) and injury free (at least healthier).

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