Zone 2 Power vs Zone 2 HR (Should I increase power to move HR to Z2?)

Yes, that may be the case indeed! In any case, I don’t thin it is expected that HR zones will follow power zones for short duration work. Jut like it takes time to reach VO2 oxygen uptake state when doing VO2 Max workouts, or the time it takes to reach Threshold HR when doing Threshold power.

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We should link the High North article that dicusses the power / HR zone not lining up :wink: as well.
When I’m in good condition mid Z2 power is mid Z1 HR

The question is: “which HR z2”… becase there are so many zone systems…

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Usually below LT1

Yes, even in the carbohydrate consumption studies you can also see a difference after the 3h mark. Most people feel their Z2 riding is too easy bcs their sessions are not long enough.

Furthermore, a solid endurance ride doesn’t have to be all z2, bits of tempo and sweet spot are ok as well.

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Lets start with Coggan remarks from 2003 paper he wrote for a USA Cycling coaches seminar on power based training:

“HR guidelines: Relating or translating the specified power levels to corresponding HR ranges or zones is somewhat difficult, due to the inherent variability of HR as well as individual differences in the power-HR relationship (even when referenced to threshold power). Nonetheless, approximate HR guidelines have been provided in Table 1, such that they can be used along with power to help guide training if desired.”

And table:

And using my threshold HR as the anchor, brought me to the which zone dilemma:

  • Coggan zone2 for me is 110-134bpm
  • Friel zone2 for me is 128-142bpm

big difference.

That bothered me, so when I got into cycling back in 2016 and 2017 I figured the thing to do was go out and do a bunch of 6-12 hour rides. Then looked at average HR and called that “all day” HR, which was 136-142bpm.

Pretty clear at that point the Friel zone2 HR align with all-day HR, for me.

Yes, but why complicate it? I would just do it the way that it was described it in that Attia podcast with Iñigo San Millán. Go by RPE. Extend duration week by week. Let the numbers be what they are, and use them more to evaluate the workout after the fact.

Interesting approach. However, doesn’t it get a bit more complicated due to the climbing/descending dynamic?…

Don’t overthink it.

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Well, it’s inevitable. I just took a look at a long ride where I averaged 144bpm but in the long climbs my HR was 155-166, which is tempo. So this wasn’t a z2 ride as the average would have you believe.

Pre power meter:

8 hours of climbing, 13:51 elapsed. Done at ‘in it to finish it’ but pace was endurance climbing and mostly nose breathing. Average HR between 134-140bpm. Average temps for each climb in F and C:

  • 44F / 7C
  • 65 / 18
  • 74 / 23
  • 80 / 27
  • 69 / 21

First climb, top of zone2 is 142bpm:

Third climb w/o the early 15 minute stop

Fifth climb:

Yeah I’m a slow climber, that was done with an FTP of around 3W/kg.

So ~8 hours of climbing over ~14 hours I think its fair game to call “all day” HR for the climbing portions only.

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and another one pre-power:

and Friel HR zones:

and elevation:

*** that was then ***

Now fast forward 6 years to the present.

Two hour Tuesday last week (outside with temps in 80s):

Two hour Tuesday this week (in cooler gym):


Ok that HR pic needs some explaining. First off HR is unusually low due to being fully heat adapted (“80s are the new 60s” LOL) and the gym was 66 degrees (108 outside). Secondly, the power increased too, and decoupling was 0.4% which is basically no decoupling of power and heart rate over the full 2 hour workout.

I dunno, it all adds up from my chair.

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Thanks for sharing. Yeah it seems that the heuristic works for you. I can climb at endurance HR and power when I want to, but in general for the very long rides I try to push harder in order to minimize time in the saddle.

What is interesting about this discussion is that is very hard to have “organic” data for long rides, given that most of us have employed some sort of objective pacing measurement in addition to RPE.

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Not that hard if you want the data, and go out and do long training climbs or flat rides. After getting a power meter, I started pacing long 90-150 minute HC climbs at mid to upper tempo. Now I’ve got zone3-zone4 data to complement the earlier zone2 data.

Key thing to remember is that context matters. And that means either planning or cherry picking data.

The only thing though is I am not looking for what I can do, but what I should do for the best training.

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well that depends on who you talk to… and whether you want to do lactate testing or not. And ‘best’ in early season is likely not be the ‘best’ during race season. It also comes down to goals and durations you are targeting. And ability to recover from the endurance work. Some coaches will tell you to simply do endurance by rpe. My coach pushes me to pay close attention to how I feel, in order to figure out the push-the-z2-power and recovery balance point.

My position on my “all day HR” methodology is that it is an ok proxy for the first (aerobic) lactate threshold. I can do epic long rides, keep my average HR under 140bpm, and usually recover quickly. So they are relatively low stress. Like doing a double century at 67% IF / avg-HR 131bpm and 2 days later going straight back into training and setting PRs.


fair, and anyways, like you and others have said a few times now, no reason to overthink this stuff. The fact that one is getting outside on the bike for 6 hours, and keeping it close to Z2 as possible, is going to do well for fitness gains, period.


Should we increase the power when the HR decreased for the same WO?

After a while I’ve noticed that my hr has become lower for all z2 endurance wo. So low that it’s almost like I’m doing nothing!

Should i increase the power or keep it like that and extend the duration?

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I adjust the power to keep the same HR. As you train in Z2, the power will keep getting an higher percentage of your ftp.


Similar question, but I am having the opposite problem from OP. Beyond a certain duration of riding in Power Zone 2, my HR rises above HR Zone 2 during the ride; should I reduce power to move HR to Zone 2??)

This past weekend, I tried to do a “proper” Zone 2 ride (based on power). I rode for about 5h 41m at a power level that was about in the middle of Zone 2 (AP 191w; NP 192w). I took a short break of about 6-8 minutes in the middle of the ride to refill my two water bottles, put some more gels in my pockets, and to pee. I set the “auto lap” feature on my Garmin to start a new lap every hour. During the ride, I noticed that my heart rate gradually increased during the ride, to the point that I getting my HR Zones 3 and 4. Following the ride, Garmin categorized it as a “Tempo” ride–that’s when I started to think maybe it wasn’t a “proper” Zone 2 ride after all.

When I ended the ride, I felt great physically and mentally. The next day, however, not so much–it was then that I realized that my “easy Zone 2” ride was actually not so easy and required more recovery than I anticipated. But I don’t know if that’s necessarily a bad thing; is it? My goal is to be able to sustain my Zone 2 power over long durations (12 hours and beyond).

If I were to do this ride again, should I (A) target the same power (193w) but increase the duration; (B) lower the target power to something closer to the bottom of my Zone 2, but hold that power constant for the duration of the ride; (C) gradually reduce my power target as HR/RPE increases?; or (D) target the same power throughout the ride, but stop if HR goes past a certain point (and what point is that?)?

Also, was the 6-8 minute break in the middle of the ride likely to significantly impact the effectiveness of this ride in terms of building endurance for longer rides? If so, what would be the best way to work around that–have someone come out and hand me bottles and gels??

What seems like a simple topic all of a sudden seems enormously complicated and confusing to me.

TrainerRoad and Training Peaks charts below:

Screenshot 2023-01-11 at 11-04-18 TrainingPeaks - Plan your training track your workouts and measure your progress

ETA: I was chased by the same dog twice during this ride, and I increased power slightly to try to get away from it.