Long Run Issues in Zone 2- switch to pace? | 80/20 Endurance

Long Run Issues in Zone 2- switch to pace?

Viewing 4 posts - 1 through 4 (of 4 total)
  • Author
  • #12503

    Hi Everyone,

    I’m a 31 year old male about 3 weeks into the 80/20 Running: 2021 Edition Marathon Level 1.

    My long run for tomorrow is a 16.1km run.

    The problem is, to stay in Zone 2 at that heart rate would mean I would be running for a very long time. My average pace in zone 2 is about 7 minutes and 50 seconds per kilometer. And even then my heart rate spikes into Zone 3 towards the end of the run as my route covers dense and humid forest. So I need to walk to bring my HR under control. A 16km run would take me well over two hours.

    When I last ran a 10k, in early May, I was able to hit a 50.36 minute time. A 5k back in March had me at 26:02 minutes. I also ran a comfortable (somewhat lost and meandering) virtual half marathon in October 2020 at 2:06. Entering these figures into the 8020 pace calculator gives me paces that are quite different from what I’m seeing when I run.

    Should I be looking to switch from HR to pace? Or is this par for the course.

    Thanks for any advice or guidance. Have a great weekend!

    Background: Ran a 2hr2 minute half marathon in October 2019 with about 2 months’ preparation. Got a respiratory illness in March 2020 that curtailed my running for a few months. Have become hooked on running since then, and have recently devoured both the 8020 Triathlon and 8020 running books.

    David Warden


    Thanks for posting on our forums!

    First, we recommend Pace or Power over HR as the primary measure of intensity. There are advantages to HR, but the net benefit falls to Pace or Power (see our automobile example in Intensity Guidelines for Running. You can always switch to Pace for free at https://www.8020endurance.com/contact/

    Second, let’s take a look at your HR zones anyway. Can you confirm:

    – What protocol did you use to identify your LTHR
    – What was the result of that LTHR
    – When was that test last performed



    Hi David,

    Thanks for this reply. My apologies over the delay in responding.

    1. Protocol: I inputted my 10k time from March 2021. That gave me a TP at 5:05. I ran and, upon reaching a 5:50 per KM pace, paused my heart rate monitor (Garmin watch w/ a chest strap). That figure gave me a pace of LTHR of 169.
    2. LTHR: 168. Zone 2= 137-152.
    3. Test performed in March 2020.

    A recent 5k (May 2021) gave me 5:24 as my TP.

    David Warden


    Thank you.

    Your LTHR validation is an acceptable method. However, the full 20-minute protocol is more accurate and given it’s been 3 months, it’s time to retest. Your LTHR could be much higher with that test (or not…)

    An upper Zone 2 of 152bmp is pretty high and should support your training well. Almost all of our workouts are prescribed based on time, not distance, for this exact reason. Don’t worry about the distance you covered (unless it is one of the distance-based workouts) just focus on the time you ran. Sure, eventually in a race you’ll have to cover a specific distance, but your total weekly load is every bit as important as your long run, and the plan supports that.

    However, I’ll go back to the first recommendation: switch to Pace. At a threshold of 5:24, the fast end of your Zone 2 is 6:12, which would take 100 minutes to run that same 16.1km, not 2 hours. Pace just may be better for you (as it is for most athletes).


Viewing 4 posts - 1 through 4 (of 4 total)
  • You must be logged in to reply to this topic.

$ubscribe and $ave!

  • Access to over 600 plans
  • Library of 5,000+ workouts
  • TrainingPeaks Premium
  • An 80/20 Endurance Book


30 day money back guarentee

For as little as $2.32 USD per week, 80/20 Endurance Subscribers receive:

  • 30-day Money Back Guarantee