Heart zone definition | 80/20 Endurance

Heart zone definition

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    Mathieu R


    I just bought the 80/20 book and there is something I really can’t wrap my head arround.
    The first part of the book explains the VT usually falls at 78% at max heart rate, alright, and that you should then in order to perform your training in the easy range to be under 75% of your max, in my case then 141 (max of 189). Then okey I should stay 80% of the time under 141 no problem.
    Later in the book I define my zones in cycling and running thanks to the table based on the LTHR (173 cycling and 178 running)
    My zone 2 in cycling is 140-156 and zone 2 in running is 144-160.
    The whole book being about not spending too much in the wrong zones, how can this be possible ?

    There are so much methods to determine zones out there and none of them give the same results, how to be sure I am in the right zones ?


    would suggest you check out the updated testing protocols here

    Intensity Guidelines for 80/20 Running


    and the updated zone calculators here

    80/20 Zone Calculator


    David/Matt why would it not let me post both links in the same post? it just literally made the reply disappear when I tried (several times)

    Also, it made me wait (too long) when having to make the second post (presumably to stop spam posting) but not conducive to people trying to help others!

    Mathieu R

    Hello Martin,

    Thanks for your answer,

    Indeed the website indicated that after performing the 20 minutes test, LTHR is 95 % of the average of the 20 minutes, which makes more sense. When the book just mention that the average IS your LTHR both for running and cycling. Maybe a good thing to change for newest version !
    Same thing applies for pace, the book is giving faster time than the website.

    However this new numbers shift my zone 2 respectively to 137-152 with running and 133-148 for cycling. This zone are still well above 75% of my max heart rate. Should I commit to these zones anyway ?
    This end of zone 2 seems quite high to me also in terms of pace and power with a 220W FTP, 183W would be the end of my zone 2 and definitely feels more than light effort

    David Warden

    @MartinH sorry for the hassle. I really appreciate you stepping in and helping out, and don’t want to make it more difficult for you to contribute.

    I’ve changed the post “throttle” from 2 minutes to 1 minute between posts. We have had spam attacks on the forums so I’m trying to find the right balance of security and convenience. Hope that’s the right value. I can’t explain the one link per post issue, I’ll have to research that to find a fix. I’m the webmaster for 80/20 (and lead Counsel, head of HR, Finance, Operations, Marketing, and I do a bit of coaching every now and then too).

    @Mathieu R I’ll have a response to you shortly on a new reply here… have to wait one minute to post ! 😉

    David Warden

    Mathieu, thansk for using our plans! We appreciate you being one of our athletes. A few things at play here…

    – VT takes place at approximately 78% of MaxHR. It could be 72%, could be 82% for an athlete. Unless you get VT tested specifically, you don’t know, but it is about 78%.

    – If your run LTHR is 178, no way your MaxHR is 189. I’m assuming you are using an age-based estimate to come up with MaxHR. Again, unless you get it tested you don’t know, and age-based estimates are notoriously bad. MaxHR is at least 15 beats higher than LT, so you’re at 193 minimum.

    So, you’re using an estimate (VT) of an estimate (MaxHR). Your LT test is an actual test, not an estimate. So, let’s use that instead to determine your zones!

    If we bump up your VT% by a couple of point and then bump up your MAxHR by a couple of points, you are well within the margin of estimates.

    Also, remember that you are not performing all workouts at the upper end of Zone 2, you have a range. Even if we take your existing 189 MAxHR and 78% for VT, your latest LT test puts you well within that range. The low end of your Zone is 133/137 for bike/run, you’re already well within the correct range. Plus, half of your easy time in the 80/20 plans is Zone 1. You’re going to get plenty of time under 141 even if we make no changes to your estimated VT and MAxHR

    I’m confident the book specifies that the run and bike are tested separately, but use the same zone %s (or maybe I’m misunderstanding the question?)

    In summary, I’m very comfortable with the test results and zones you currently have.


    Mathieu R

    Hello David,

    It is great to see you so reactive on the forum and involved with helping athletes

    To give a bit of precision too get my maximal heart rate I monitored the last 6 months of training and added 2 bpm to the maximum I ever recorded hence 189, confirmed by another formula a bit more complicated than 220-age which does not work at all for me.

    Martin helped me by indicating the website calculations are more actual, and based on the 20 minutes test I obtain now LTHR of 169 running and 164 cycling which adds up with your answer.
    I am going to give a chance to the lvl 2 program given in the book !


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