Pace in Zone 2, HR in Z3 or 4

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    I expect this is a common phenomenon around here.

    I’ve been running in my Z1/Z2 pace zones now for a bit – middle distance long runs – but I still see my HR typically in Z3 for the majority of the run.

    Now, it could be that my HR monitors are just inaccurate, but wondering if this is probably a sign of not enough base kms / lack of fitness?

    Should I be dialling back the pace until I get my HR in the correct zone?

    Matt Fitzgerald

    Which method did you use to determine your pace zones and how recently were they last adjusted?


    I’m having a similar issue just the other way around. I did the first workout in my plan today and I did good staying in the HR zones however when I finished the workout and looked at my pace zones I was in Z1 the entire time while I was between HR Z2-Z4 for a majority of the run. I used the pace calculator from the 80/20 site to figure these numbers out. Maybe im doing something wrong as I am new to this?

    Matt Fitzgerald

    It is normal for pace and HR zones not to align perfectly. They are two very different metrics. Our zones aim to be one-size-fits-all, but each individual runner has a unique pace/HR profile. This is why we recommend that each runner choose a primary intensity metric and focus on it.

    Which specific testing protocol did you use to determine your zones? There is a way to get HR and pace zones to align better, but I’ll need your answer to this question before i explain it.


    I have used the 20 mins time trail test to determine my threshold HR, POWER and Pace.
    My Pace and Power zones are nearly identical. However my HR zones are not correlated with the pace and Power zones.

    If there is a way to align this better, would really appreciate that.

    Matt Fitzgerald

    Here’s what I suggest. Next time you run, warm up and then settle into your LTP or rFTP, take your pick. Wait for your heart rate to plateau. Once your HR is steady, note the number and enter it into the calculator. That should give you zones that better align with your pace/power zones.


    Hey Matt,

    It looks like I’m still having a similar issue as noted previously here in this thread. My original numbers were based off a 10K run which was completed in 1:01:51 average pace of 10:03min/mile. This is still my fastest 10K time.

    Fast forward 2-3 months (per the last time I posted here) where I yesterday completed a 45 minute foundation run. Distance ran was 4.5 miles at an average time of 9:59min/mile.

    Per TrainingPeaks I checked my Pace by Zone (which is the intensity I have chosen to focus on) vs. my HR by Zone.

    Pace by Zone (time spent in each zone; 45 minutes total) per TP:

    Z1: -10:34min/mile 6:58
    Z2: 10:34-9:21 min/mile 31:43
    Z3: 9:21-8:41 min/mile 6:17

    HR by Zone however, found that most of my run was done from ZY – Z5 where I spent 7:44 in ZY, 11:11 in Z4, and 21:01 in Z5.

    For another point of reference, my last long run on Sep. 11th was 1:16:50 with a distance of 7.53 miles at a pace of 10:12 min/mile. (Which I just checked and my HR by Zone shows that most of this run was done in Z3 while Pace by Zone shows almost all of the run being done in Z2. This was overall a more comfortable run then yesterday’s foundation run.

    Hopefully all of this gives you enough information to know where I’m at at this point. I’m not sure if I should change my numbers or if I should just leave them the same since the intensity I’m focusing on (Pace) is still being ran for the most part in Z2.

    Thanks for the taking the time to read through all of this! I know it’s a lot but I just want to make sure I’m setting myself up for success here.


    David Warden

    Zeek and others on this thread,

    HR and Pace (and Power) zones will only align under specific conditions, which include:
    – The thresholds must be identified within the same threshold test, using the field test protocol in our document You can’t identify LTHR on one day using method A and test threshold Pace on another day using method B. They must be identified done in the same test.
    – HR is an indicator of how your body is responding to an activity. Pace and Power are outputs. HR is influenced by time of day, temperature, humidity, indoor vs outdoor, stress, sleep, when you last ate and I suspect stock market performance (I jest on this last one). You can have a swing of 20 bmp for the exact same pace based on all of these factors. Therefore, your LTHR is really only accurate if you train under almost identical conditions to your LTHR test.

    The answer? Don’t use HR. Use Pace or Power and ignore HR. Or, at least don’t use two at a time. Commit to one intensity measure and stick with it. Trying to mix and match will drive you crazy as HR is a moving target.

    Many athletes ARE able to sync up HR and Pace/Power IF they test frequently and train in a relatively similar environment and same time of day each day. It’s possible, it just takes an understanding of how HR responds.

    Specifically, zeek, using a 10K from 3 months ago is not a reflection on your current zones. Test more often, and use our field test protocols from and you have an increased chance that HR and Pace will align.



    I trained by heart rate for a while. For the most part, HR will get the job done and keep you honest on your easy runs. But there are some drawbacks, as David mentioned.

    Anyone training by pace, power, or RPE could probably tell you about times when a run was unmistakably easy, but their heart rate didn’t match the effort. That happens from time to time. Everything feels super easy, but the heart rate ends up above zone 2. My thought is that it doesn’t happen often, so I don’t worry about it.

    The only other thought is that if your heart rate is up in zone 4 on easy runs, something might be off. Maybe your zones are incorrect. Or maybe you’re pushing the top of zone 2 when your body is more fatigued and would actually prefer an easier effort. Just my thoughts.


    If you are training for a race you need to train to pace; when you begin the race specific segment your plan you must have your paces established.

    My experience is that heart rate has no role during a race build. Heck, I can sit in my armchair and move my heart rate with thought alone – there are just too many variables that impact heart rate.

    But that is not to say there is no place for heart rate training. I am beginning to introduce Spin Cycling into my training and heart rate is the only means that I have to measure my progress building local muscular endurance. The divergence between the activities is huge at the moment, I’m out of breath well below my running thresholds for a given heart rate. I’m slowly seeing improvement but it all takes time. Likewise, if you are running for fitness (not racing) below the lactate threshold heart rate is a great tool to measure compliance and performance.


    I like using HR Zones for Easy runs. Admittedly I am a slave to my Garmin stats, but on easy runs I generally ignore the pace and go by HR rate. That makes it easy to run by feel, too. I don’t know about others, but my zone-2 heart range is pretty wide (15 beats) and if I include my zone-1 it’s very wide (30 beats). If I do glance at my pace or time elapsed, I could decide to push it a little and still remain within zone-2.


    Yeah, for racing, I really wouldn’t worry about heart rate. The excitement always gets my heart rate higher than it normally would be.


    I’ve been following the Garmin “Training Effect” for some time now. It basically scores your activity with heart rate activity.

    Example: Today I ran a sixty minute foundation (RF29) run right on the estimated pace (from the Training Peaks workout summary). The planned TSS and rTSS were within one point. Garmin Connect reported the Training Effect to be 3.2 or Aerobic Base primary effect. Spot on. On July 4th I ran a 5K, out of shape, but intending to run a tempo pace. My heart rate shot to Zone 5 from the start and I struggled to hold my tempo pace, largely because the start of the race was on a significant incline. Garmin Connect scored the Training Effect at 4.4, Primary Benefit VO2max. Not what I expected, but spot on – I really had to work that day.

    I’ve noticed that the Training Effect metric does a good job summarizing the 80/20 Workouts. The data analysis provides a more meaningful report on heart rate than trying to make sense out of the raw bpm data.

    Useful? I don’t know, but I suspect that it will be in the future as advanced analytics matures and moves to our wearables. For now I believe it is a reasonable check that your 80/20 workouts and your execution are in sync.

    Matt Fitzgerald

    I like the addition of the Primary Effect. My device doesn’t have that–it just gives the numbers, which results in a lot of apples-to-oranges comparisons.


    Yeah, there is something going on that is hidden in the data.

    This past Monday I ran the RFR9 (Fartlek Run) and pretty much hit my targets. Interestingly, my peak heart rate never reached my threshold. Not surprising since each surge only lasts 20sec.

    Garmin scored the workout primary Base/3.4 Aerobic/1.5 Anaerobic. Seems about right, but they are catching something that does not show in the bpm curves on Garmin Connect or Training Peaks. Could be they are using heart rate variability?

    Doesn’t matter to me how, but there is comfort knowing that I am getting the desired training effects. It would be nice if we ever get to a place where we can get real-time training effects during a session :-).

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