Polarized training: Where is the "real" endurance zone?

Hi all,

I have been on the Polarized training approach for more than a year, this is my second winter on it. I’ve listened to several of Dr. Seiler’s talks, but I still don’t think I truly know what my HR range should be for endurance cycling (the 80-90% where I am in zone 1 on a 3-zone polarized model).

I am 54 years old, my max measured HR doing all-out sprints after a couple of long rides this year was 181-183 BPM, and TrainingPeaks says my LTHR is 167 BPM. TrainingPeaks says my calculated Aerobic Capacity zone is 115-139 BPM. But there is a huge difference in RPE between 115-123 BPM, and 125-139 BPM. At 115-123 BPM, it feels fairly easy but I still get tired after a two to three hour ride. I’ve been typically aiming for 125-132 BPM and that is much harder for a two or three hour ride. At the higher range (125 BPM and above) I see quite a lot of cardiac drift over time; at the lower range I still see some cardiac drift but it is less. Lastly, I would add that my LTHR calculated by TrainingPeaks feels very high. I would put the bottom of LTHR more at 158-160 BPM based on RPE during 8-15 minute FTP intervals.

So, without access to a lab, how can I figure out what my endurance zone (one) should be for Polarized training? What is the bottom of the low end that is still beneficial (how low is too low)? How high is too high? I don’t want to do junk miles (too low) but I also don’t want to be going too hard (also junk miles) when I want to be doing polarized endurance training. Please let me know your thoughts and thanks.


I think I would be inclined to go with RPE. If the intensity begins quite easy but starts to feel harder 2 to 3 hours in then thats probably about right.

Your max and threshold HR numbers are almost identical to mine and I try to keep below about 130bpm for basic endurance. Tempo work using @steveneal style HR ceiling I try to keep under 145bpm



How many hours do you normally train each week? Or if they vary what is your minimum and maximum normal?


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@steveneal In the summer, I ride ride six to seven hours a week with one hour of heavy weight lifting. In the fall and winter, I ride four and a half to five hours a week with 2.5 hours of heavy weight lifting (over two sessions). Thanks for any thoughts you can share.

Hello, I think with those hours you might be best following more of a pyramidal approach that polarized.

So you would need to do more tempo sessions, and maybe even include some tempo inside your endurance rides to increase the aerobic training stress with the limited hours.

The key here is keeping the tempo at a perfect level. Without any lactate or moxy testing, you are likely best to add some more time in the 78-83% max heart rate range for tempo, and your endurance is likely in the 65-74% max heart rate range.


Thanks @steveneal. Dr. Seiler says the polarized training approach works even down to five or six hours a week. I’m wondering if you disagree with this, or why you would recommend a pyramidal training approach? One thing that can be hard with tempo sessions and weight sessions is, it takes quite a bit of time to recover from weight lifting sessions so it might be difficult to do two of those a week and do tempo rides as well. Please let me know your thoughts and thanks again.


It may work down to as low as 5 or 6 hours, I would just approach things differently.

The one thing that gets confusing is how we create our zones when having these discussions.

So maybe pyramidal isn’t the name for what I would do, but I would add a combination of Endurance and Tempo into the plan.

The way I define Tempo though is likely easier than most. If you are thinking of Tempo as a % of FTP that would likely be too hard.

Example, current numbers on an athlete I work with.

Hero Bar wko

Zones from WKO ( I don’t use these but for example )

I have this athlete doing endurance at 180-210w and tempo at 225-235w at the moment from testing using moxy monitor.

I continue to monitor this monthly and make sure the two zones are accurate.

You will notice that his tempo is right at the bottom of calculated in wko, many would not ever train right at the bottom of the zone.

If I were to use lactate in the above athlete, when doing endurance he would be right around 1.2-1.7 mmol, doing tempo under 2.5 and stable. The stable part is where this works. If I were to have him do tempo at 250w, which he could handle, there would be lactate accumulation during the tempo sets, which then would make it harder to recover from.

When doing the tempo in a steady state over 30-40-50-60m at this slightly lower level, I can get him to do a lot more work, and recover in 24 hours.

Last Feb his tempo ability measure the same way was 255w, the goal will be to get that back to 255w by Feb…or increase it again a little higher if possible. 51 year old mtb athlete.


The other thoughts that come to mind for YOU are.

What are your cycling goals? What type of cycling? What duration of events if any?

The strength training - I would want to dig a little deeper - there are many ways to improve strength and it sounds like you have a pretty challenging program with some possible interference towards the bike training.

Knowing your goals, your feelings towards your current strength plan, how it is working for you, where you are feeling limited, these are just some parts of a discussion that might arise in a conversation when trying to figure out the right approach for someone.

Sorry for taking this sideways, but there is likely a bit more to this than just the name of polarization or pyramidal in helping with the plan.


To answer the original question, I use;

60-75% max heart rate for endurance
78-83% max heart rate for tempo


Hi @northk. Great question! I’ve wondered the same thing myself. My numbers are very similar to you except I average more like 10 hours per week. I’m not a coach, nor an expert, so I really don’t know but here’s what I’ve tried to apply. I’d love to hear more on this.

For my endurance rides, I’ll target the harder zone (130-145 bpm) if:

  • It’s a shorter ride (1-2hr)
  • I’ve only got one intensity day that week
  • I can’t do any really long rides or my total volume will be lower than normal

I’ll target the easier zone (115-130 bpm) if:

  • It’s a longer ride (2-5hr)
  • I’ve got two intensity days that week
  • I’ve got other long rides planned or my volume is high for that week
  • My life/work stress is higher than normal, poor sleep, hangover, etc

How low is too low? Didn’t Seiler day that less than 50% of HR reserve is too low? Resting HR + 0.5 X (Max HR - resting HR).

How high is too high? That probably depends on what else you have planned that week. What type of intensity sessions do you do and how often?


@steveneal, wow a lot to think about here. Thanks. It is possible that doing strength training with heavy (for me) weights twice a week might interfere with pure cycling performance.

On the other hand, when I lift weights like this my knees, hips, back, neck, arms, torso, shoulders, even my feet and ankles…all feel good. No injuries, no pain (other than exertion) from riding. And the years I haven’t lifted weights, everything hurts and I get easily injured from riding (despite having had six professional bike fits in the last five years).

By the way, “A hero” you are coaching sure has some mad watts he can produce!
Thanks again.

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@robertehall1 thanks! This time of year I do one hard interval ride, two heavy weight lifting sessions (an hour + ten minutes each), an endurance ride for 1.5+ hours, and another endurance ride for 2+ hours each week. Polarized training appeals to me because with the intensity of the interval day plus the two weight days, endurance rides is about all I have left in my body.

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My training, and 3 of the club members I’m coaching, is mostly Pyramidal, for about 400-425 hours per annum (20-22,5K TSS).

Most of the Z2 (5 zone) rides are in the upper half of the zone, as most weekday rides are 60-90 minutes depending on the mesocycle.

There are two intensity sessions per week; one if anyone feels tired. During the 2 build phases, it is mostly polarised, as it is Z5-7 intervals and lots of Z1 recovery in between intervals.

During the Base mesocycles, the recovery is mostly upper Z2, unless the person is struggling.


A lot of interesting answers. But these don’t answer the original question or over-complicate the topic. Dr Seiler often explains that many amateur athletes train too much in the tempo zone (zone 2 according to Seiler, zone 3 in the 5-zone model) because zone 1 (according to Seiler) or zone 2 (in the 5-zone model) feels too slow for many of these athletes. And that’s exactly the point. If you follow the polarized training concept, then (for you) 115-123 BPM is the right heart rate range (Seilers Zone 1) for pure endurance training. Training in the 124-139 BPM range is to be avoided (This is Seiler Zone 2 and he calls these “junk miles”). That’s the main difference to the pyramid model or to training by feel. So in your case, 80% training in the 115-123 range and 20% training in the 140+ range (high intensity intervals) would be the right orientation if you want to train according to the polarized concept. All the other ideas here are cool and worth of consideration but have nothing to do with polarized training. So the short and simple answer to your original question is: 115-123 BPM (if you want strictly follow the polarized concept according to Seiler. And yes that feels very slow :slight_smile: but it is correct and has the desired training effect.


@flknit thanks for your response. Yes, 115-123 BPM feels really slow and it’s hard to be disciplined enough to do that for 2-3 hours!

There are actually tests to determine the aerobic threshold and it does vary from person to person, largely based on lifestyle (time spent active each day), years of training and time spent in zone 2.

As a coach I watch heart rate drift and fatigue over time on a single multi hour ride, but the most precise method is to utilize a lactate meter, targeting 2 mmol/l or below.

That said, I rarely find an athlete with an aerobic threshold below 68% of FTP (in using watts rather than HR) and utilizing too low a target is significantly better than being too high, so this is one instance where you ‘aim low.’

It is also rare to find an athlete who doesnt regualrly (at least weekly) ride multiple hour rides with an aerobic threshold above 75% of ftp.

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@steveneal With Lactate levels at 1.2-1.7mmol, are you looking to work at the high end of this athlete’s Fat Max range?

Recently, the Norwegian Triathlete’s have been having great success. They describe their “Threshold” training at around 2.5 mmol, to train just below their LT2.

I just found it interesting that you honed in on this same level. Any thoughts?

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@shawnfife Sorry but I wouldn’t know where to start with thoughts? It is really from years of taking lactates in the field during workouts of all types, even taking lactates during mountain bike races every lap on many, many athletes. Taking lactates during tempo sessions.

When I was doing this in the actual training world, I was always surprised that what I saw in actual training was not what I really heard or read of what I should have been seeing.

The other part of this is that the Norwegian thing really isn’t new to me either. I had a friend who was five time national cross country ski champion, with a best world championship result of 7th in the 50k skate.

Many years ago, the Norwegian skiers used to use 2.5 mmol for endurance ceiling, then 2.0 then eventually 1.5 as they found more and more the level people could handle when doing lots of volume.

My friend actually stayed with me often when racing Nationals, and resting lactates were taken daily and mutlitple times throughout the day leading up to the races. It was interesting to watch the changes and see him perform. At this time I was just racing mountain bikes and skiing for fitness, just happened to be able to learn from a life long friend who was pretty talented.

I think the biggest thing I can say here is that we really need to take our own measurements rather than assume we are training in a certain zone.

The only way the Norwegians know what zone they are in is because they are measuring. Many of us want to take one test and hope we see the same information for months and months during our training, but this is not the case.

So great athletes often have great body feeling. Many of us more regular folks often need the science measurements so that we can develop a better body feeling and learn.

I think there have been a few good podcasts with the Norwegian triathletes, their coach and how long they have been working together. So the results we are seeing know are from years of work, likely at these levels we are hearing about know that they are successful.

Sounds like a fun topic to just chat about over coffee.


Probably some of the most insightful words on these forums!

I would add that Kenyan runners and ultra-elite marathoners are great sources of lactate-based training techniques too. There are other pockets of lactate disciples in various endurance and mountain sports, but so far cycling remains dominated by what I call the CI approach (all carbs and intensity) - but it’s slowly changing…

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I was gonna ask about this as well. In my experience and in the research I’ve read, the majority of non-elite cyclists have resting lactate levels around 1.2 to 1.5., so tempo would be a fair bit higher.

@knate I am not so sure resting lactate can be directly related to working lactate.

I could have a resting lactate of 1.7, then start a step test, it would drop slowly in the early parts of the test, and may only come back up to 1.7 before deflecting at my LT1.

Here is an example of a 44 year old cyclist, different numbers but you can see this is a likely trend of someone with the way a lactate test will look like if started easy enough. Often lactate tests (or any tests rather) are started at an intensity that often drives the lactate early, which then inflates the rest of the test, at least the early stages which we are looking at for LT1.

If the second and third lactates are not lower than the first, I feel the test either started too hard, the increases in wattage per step were too high, or both. The test protocol should match that of the fitness of the athlete, this is a one area where test protocols are kept the same too often.

I would keep it simple at true to polarized in the 80% or less maxHR is you easy days and 90+% max HR is your hard interval day/s. Polarized needs to be based off max HR NOT threshold HR. You can get caught in the weeds even with the simple 3 zone model of polairized but it is all about easy vs hard days. 80% of rides easy at 80% of less max HR and 20% rides hard at 90+% max HR. Allow the power to be what it is if you are using a power meter based off the % of max HR. Power will take care of itself. When one of my athletes has a string of 3-4 easy days in a row I might use a cieling of 75% max HR to make that ride even more easy. RPE is a good way to measure the strain of you workous with thoese easy days being 2-4 RPE and hard days being 8-9 RPE.
Hope this helps.