The Death Of Heart Rate Training Zones.

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Yesterday morning, I was on running along an asphalt path beside the river.

Committed to the plan for the workout, I was carefully gauging intensity, calculating pace, and watching my GPS.

Totally geeked out.

Sadly, I was barely noticing the morning sun glowing through the trees, the clean sparkle of the gently flowing river, or the intense green springing up besides the path.

Instead, it was just me and my gadgets, huffing and puffing away.

But then I stopped.

Was this really what exercise was meant to be? Fighting through a workout as a beeping, vibrating watch on your wrist slave-drives you step-by-step? Was I turning into a “rat on a wheel”?

This was madness.

Now I'm not going to deny the benefits of monitoring your intensity, having concrete numbers to track your training progress, and ensuring that you're not simply slogging through “junk miles”. As a matter of fact, in the Get-Fit Guy episode “How To Use Heart Rate During A Workout“, I explain the value of heart rate training zones.

And that's not the only nod I give towards heart rate zone training.

I also include heart rate zone monitoring instructions in my triathlon training plans and books. For example, here's a clipped heart rate training zones table from the Triathlon Dominator package.

Heart Rate Zone % of your LT Description
Zone 1 Level:





70-76% After hard workouts, very easy workouts accelerate recovery more than complete rest. Easy aerobic training stimulates circulation, which accelerates tissue healing response. Intensity is enough to increase blood circulation and trigger a growth hormone response, but not intense enough to cause significant muscle damage. This effort range is also used during long endurance efforts (over 60 minutes), in which it can be more fatiguing due to energy and fluid depletion.
Zone 2 Level:




77-85% This zone will also feel very easy (“conversational” effort). Training at this intensity primarily uses slow-twitch muscle fibers, since these fibers provide more most of the mobility for events lasting 2 minutes or longer, workouts at this intensity should comprise most of your training. Training above this intensity will not significantly overload your slow-twitch fibers, which you are attempting to train to become more efficient at using oxygen to produce energy while conserving carbohydrate stores. This intensity is important for training the body to use fat as a fuel, especially for individuals who compete in events lasting more than two hours. Although it will be difficult to keep your intensity low on these days, performing your endurance efforts at a higher intensity than Zone 2 will reduce the effectiveness of your harder workouts on subsequent days by fatiguing muscle and depleting carbohydrate stores in fast-twitch muscle. This can lead to overtraining.
Zone 3 Level:

Muscular Endurance below AT




86-95% During an endurance workout, your intensity may reach this level on hills. The body is still primarily functioning aerobically, conversation is possible, and burning in the legs/shortness of breath is minimal. However, the intensity is too high for maximal stimulation of the slow-twitch muscle fibers and fat-burning. As intensity increases from zone 2 to zone 3, oxygen debt becomes greater, and since it takes more oxygen to burn one calorie from fat than from carbohydrate, more carbohydrate and less fat will be burned. If your lactate threshold is low, you should perform intervals, hills climbs, and race pace training in this zone.
Zone 4 Level:

Muscular Endurance at AT




96-103% Lactate threshold (LT), also called anaerobic threshold (AT), is the highest intensity at which the body can recycle lactic acid as quickly as it is produced. In zone 4, the aerobic and anaerobic systems are working together in balance to provide energy for exercise. Anaerobic metabolism is slow enough that lactic acid, the substance that makes muscles burn during hard exercise, does not accumulate. At this intensity, you are working very hard, but can still maintain exercise because lactic acid levels in the blood and muscles are steady, not increasing. Increasing the intensity just slightly causes lactic acid to build up and brings premature fatigue and delayed recovery Training near lactate threshold decreases the amount of lactic acid being produced and increases lactate removal at a given output. At this intensity, the fast-twitch fibers can be trained to produce less lactic acid and the slow twitch fibers can be trained to burn more lactic acid, both of which raise the lactic acid threshold and allow you to work harder at a higher intensity. Since lactic acid levels are controlled, recovery from this type of training is quicker than from other high-intensity training methods, therefore zone 4 training has the best cost:benefit ratio of any type of training.  When you experience “rubbery leg” syndrome, a marked increase in breathing difficulty,  you have reached the point where lactic acid accumulates at a faster rate than it can be removed, which will rapidly decrease your ability to maintain a steady effort, and take you into Zone 5.
Zone 5 Level:

Sustained speed




104-max% Intensity now exceeds the lactate threshold and the body is stressed in its ability to withstand high lactate levels and remove lactate. In Zone 5, lactic acid builds up quickly, so this intensity cannot be sustained for long periods. This intensity is anaerobic, so your body cannot use oxygen, which limits efforts in this zone to about 60 seconds maximum. Zone 5 training is a very effective means of increasing speed and performance, but because lactic acid levels become extremely high, this type of training requires extensive recovery between both workouts and intervals. Zone 5 training is beneficial, but should not be overdone. In addition to increasing an athlete’s sprint power, training at this intensity will improve an athlete’s economy, or efficiency. High levels of training in this zone is another common cause of overtraining. Typically, the only work done in this zone is interval training and hill repeats.
Zone 6 Level:

Explosive speed



max This intensity can only be maintained for up to approximately 15 seconds. Athletes who need development in the fast-twitch muscles, explosive power, or improvement in running mechanics should train at this level. These type of workouts are typified by short, explosive intervals followed by long recoveries. Every athlete should take this kind of training seriously, because it can take over 48 hours to recover from a medium to high repetition workout in this zone.

Precise instructions like those in the heart rate zone training chart above, combined with a knowledge of how your heart rate affects your rate of fuel utilization and physiology, is certainly important – whether you're trying to lose fat or do an Ironman triathlon.

As a matter of fact, if you really want to geek out on this heart rate zone training stuff, you should watch this free webinar “Eating For Endurance”, in which I explain the relationship between training zones and fuel utilization. It really will help you understand why a basic understanding of heart rate training zones is so important.

Monitoring heart rate becomes even more important for A) beginning exercisers, who are just getting into working out or training more precisely, and thus need to really monitor how their muscles and breathing feel at specific heart rates; and B) people who have been assigned a workout by a coach, who want to share their workout data with their coach.


Sometimes you just need to unplug.

After all, a huge component of exercise is play. What fun is working out, swimming, biking, running, lifting or competing in sports if your exercise turns into feeling like a freaking job?

And that's not all.

You need to learn how to feel what happens to your body when you move, and not just rely on a smart computer on your wrist to tell you what's happening to your body. For example, once you know your “Zone 4” heart rate, and you've done a few workouts at that heart rate, you need to be able to go out and replicate that same feeling by listening to parameters like your breathing and your muscles.

You need to be in touch with your body, without the help of electronics.

And if you're exercising for competition, like triathlon or marathon, I'm a huge fan of training with a monitor, but racing by feel. Racing by feel works really well if you're experienced with competition. For example, my first few Ironman triathlons, I actually used two different heart rate monitors (1 for the bike and 1 for the run), but now I don't use a monitor at all. I just go by feel, because I've educated my brain to know what is happening to my body and what I feel like in each of the heart rate zones. This also keeps me from getting confused by the effects that adrenaline, caffeine, heat and other variables can have on heart rate.

There you have: I'm not totally against heart rate zone training.

But what happened yesterday morning?

I said, “Screw it”.

Death to the monitor.

Not only did I immediately stop running, but I veered off the path, charged through the trees, threw off my shoes, and plunged into the icy river. Swimming like Tarzan, I thrashed across the entire river, then swam back to shore- my muscles freezing and my mind alert and alive.

Then I did it again.

The run home was both cold and warm at the same time. My teeth were chattering, but the warm sun felt good on my goose-bumped skin.

And I played. Every time a bicycle passed, I charged after it like a cheetah hunting a gazelle. I said a friendly “Good Morning!” to every pedestrian I encountered on the path. And that kept me occupied all the way home.

I admit that I felt a bit guilty during breakfast. After all, rather than “working out”, I had just turned the latter half of my exercise routine into playtime.

I imagine the guilt will go away after a few weeks of playtime.

Thanks for reading. How do you feel about training with a heart rate monitor? Do you ever turn your workouts into playtime? If so, how do you do it? Leave your comments, questions and feedback below.

Ask Ben a Podcast Question

17 thoughts on “The Death Of Heart Rate Training Zones.

  1. Bob says:

    There are plenty of studies proving that the human body does not have Lactic Acid in it.

  2. juiceguy23 says:

    Hey Ben, I'm a newbie with monitoring heart rate. I've completed four marathons and basically I've ran so much I can "run by feel" but I just started swimming. I noticed you mentioned swimming here but it seemed like you talked more about hrm when biking and running. Do you monitor your hr when you swim too?

    1. I never monitor HR when swimming. Too distracting!

  3. Jeff says:

    I think if you are testing it's good to have some data along with RPE.

  4. jeff Hoening says:

    Great post, Ben. The best thing I've done for my running is selling my Garmin and using a Road ID on my left wrist and MapMyRun to map my distances. There's no better telemetry than than your own body. With SO many things that impact a run/bike/swim such as (but not limited to) weather, sleep, food, and stress,. it's really silly to compare a workout from one day to the next based on pace or HR. Plus HR monitors can be notoriously inaccurate and effected by sweat, weather, contacts, age. I'd heard a couple of pro triathletes that do not plan out their training schedule, but go by feel from day to day – hammering when they feel great and recovery when they need it. This SO put the fun and joy back into running for me. Try it, you'll like it.

  5. Jim McIntosh says:

    Yes, I will often wear but ignore data while I am exercising and look at it after the fact. Yep play is important and should be at least a bi-weekly affair, the most successful HS distance coach had his boys do a "river run" every Friday that was play, romping down a small creek.

  6. Craig Huggart says:

    I love it, Ben! Great advice: get know what the zones feel like and then go by feel.

  7. Great post Ben,
    It's interesting how we operate in alternative worlds – I'm constantly encouraging Indoor Cycling Instructors to introduce HR zone based structure into their classes.

  8. Rob says:

    Just bought a Polar RS300x a few days ago so this could not be more relevant. I agree with the whole "plugged in" vibe you're talking about. Sometimes It's nice just to get out and enjoy the fresh air. I found your breakdown of the zones really usefull too. Thanks.

  9. Kelcey says:


  10. Jerry says:

    I often go through cycles of training with gadgets and training without. Frankly, I've not noticed a huge difference in my race performance either way. Believe it or not, there are a good number of triathlon coaches (including a couple of ex-pros that I've personally spoken with) who do not use ANY kind of gadget in their training methods – no power meter, no heart rate monitor, no gps. There's also a group of online triathlon coaches that are mostly active in other parts of the world, but sell stock training plans that have the same philosophy. RPE only.

    I have a tendency to geek out, if given the chance. It seems the more I do that, the more I slide into my hobby becoming a like j-o-b. It's liberating to lose the gadgets. But at the same time, difficult for type-A personalities to wonder…"Am I training to my maximum potential?"

    I chucked the power meter on the bike this year. One step at a time, I guess…

  11. Being a trail runner almost exclusively, I often run just for fun. Taking pictures, chasing rabbits, yelling at and chasing deer. And when I’m with my friend John getting off the trail and exploring creek beds, enjoying cliffside views, and what may be through the woods.

  12. Did Art DeVany write this? :)

  13. Paul says:

    I make one run a week playtime. That way I feel fresh and less attached to the watch. I don’t even bring it some time. I have been running for 30 years and still like to get out and have the sun on me and enjoy myself.

  14. bruce says:

    Great article.

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