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Heart Rate Zones: A lot Questions & Confusion + Display HR training

Hello folks!

I've had the Forerunner 965 (and also an Edge 830) for a few weeks. The values for the heart rate zones are so questionable that I have to investigate:

Here is the list of my questions:

1. With the Forerunner, there are sub-items "Zones" and "Sport heart rate" in the Garmin Connect app in the user profile / heart rate and power zones / heart rate.
a) What is the difference? What is "Ranges / Default" for?
b) Why are the % values for "Standard" completely different from the % values for the individual sports?

2. When setting the heart rate zone by HR Reserve, extremely low % values are displayed. This is completely illogical, because HRR is HR max minus HR rest. This means that HRR is logically a lower value than HR max, so the % values cannot be so low. It calculates completely wrong values with it.

3. When I calculate the HR zones for cycling in Garmin Connect Web for the Edge 830, Garmin suddenly takes completely different % values than are used with the Forerunner. That doesn't add up at all. One should assume that the HR zones are calculated uniformly - regardless of which device you set them with. At Garmin, the Forerunner division doesn't seem to know what the Edge division is doing and vice versa.

4. When I do a heart rate based workout with the Forerunner, there is another value that I don't understand below the heart rate and the time (the countdown). I have no idea what this value (which seems to me to rise irregularly every now and then) means. I couldn't find anything about it on the web either.

5. And last but not least, a point that is not a question, but just expresses my amazement at what Garmin produces: if you download a triathlon training plan, the training zones listed there (No. 1, 2, 3, 4 .. .) do not match the Garmin zones. What is in the training plan 1 corresponds to zone 2 in Garmin. Therefore, in order to be able to use the plan, you have to edit each individual training session and change the zone from 1 to 2, from 2 to 3 etc. everywhere. It's just unbelievable that Garmin doesn't make it and don't seem to care to fix that.

I hope you can give me answers to these questions. Thank you very much.

  • I am not an expert on training zones, but maybe some of my observations help:

    - Some Garmin units (esp. new watches) have a feature where you can configure different training zones for different sports. You have a default setup and you can use this default or override it with custom setup for different sports like running or cycling.

    - For HR Reserve I would expect lower percentages for the same zone setup, because you start at your resting heart rate (0%), so all percentages (except 100%) denote higher absolute HR compared to Max HR percentages.

    - For training plans, make sure that you don't mix power and HR zones. Also note that zones do not correspond to a value, but to a range, which is not very clear in your spreadsheets.

    - Garmin defaults match the common simple setup where zone 1, called warm-up, is from 50% to 60% of Max HR (see https://www.whoop.com/thelocker/max-heart-rate-training-zones/). This is different from your spreadsheets where you separate zone 1 and warm up.

    - It's easy to create a mess with zone setup by setting it up in different places, changing the number or type of zones, or letting Garmin update reference values without checking if the values are sane. I would recommend that you determine the setup you want and make sure that it's correctly set up on all your devices. If you don't know what setup to choose, start with something simple - determine your max HR (estimate from age or perform a ramp test) and apply the default setup cited above. Then observe how it works for you and tweak where it does not.

    - I would recommend considering power or pace based training as well. My heart rate started to make much more sense to me when I started comparing it with power measurements :-) In any case your heart rate will be lagging behind and be affected by your general condition and tiredness compared to your muscle effort.

  • Thanks for your answer.

    - I know that there are sport-specific heart rate zone settings and a default setting. But the default setting is so different from everything else that it's very strange.

    - HR reserve is explained by Garmin like this: "HR max - HR rest = HR reserve". So in my case I take 181 - 54 = 127. That's why I expect higher percentages to calculate the zones. If - as you write - I simply set HR rest to 0%, then I'm more likely to be back to calculating HR max.

    - By the way, Garmin's standard values (whether for standard, running or cycling) do not match these usual standard values in your table (on this website) - at least on the Forerunner 965.

    At the moment I'm comparing umpteen variants (Garmin Forerunner 965, Polar, 2peak, various sports doctors who provide computers) and I've noticed that there are some very big differences here. This is completely insane and - it seems - highly unscientific. In addition, I not only have to derive values that are reasonably suitable for running, but also for cycling. That's the next construction site, because 5 to 10 strokes less is just too big a difference....or I really have to increase my running zones. I.e. check again how high HR max really is when running, by how much higher this value is than when cycling.

  • For what it is worth, when I use Settings > User Profile > Heart Rate & Power Zones > Heart Rate > Zones > Reset Zones on my Forerunner 965 then I get the standard zone setup that matches the table in the link I shared earlier.

    I am not surprised that you might need to tweak your setup for running vs cycling, since different muscles are differently involved in each of the activities. However, during my training I can easily get 5 to 10 bpm difference at the same stable power output due to external (temperature) or internal (tiredness) factors.

    If you want to be scientific, you need more measurements and need to compare and correlate different signals. Determine your max HR for running vs cycling. Determine your critical functional power or pace (the one that you can sustain for a long time, like 1h - see FTP, CV or CSS). See how your heart rate compares to workouts in different power or pace zones, under different circumstances and over the duration of the workout (as you get tired, esp. during HIIT). I think only then you can start drawing sensible conclusions about a heart rate zone setup (or setups) that is (are) adapted to you. Without all this, and without keeping this updated every 4 weeks or so, the default heart rate zone setup (the one under the external link which is what Garmin should produce when you reset the zones) is probably as good as anything you can get from general rules derived from a wide population.

  • Hi tosonny,

    here is a video about heart rate zones by one of the top scientists on endurance training, which contains a lot of insight: https://www.youtube.com/watch?v=NPwyk9B0j-s

    To me, heart rate zones are just a way to communicate between athlete and coach, and there is no right or wrong way to define them. This can also mean completely different zones for different sports. As you can see in the above video there are two physiological "cut points" that are often used as zone boundaries, which is VT_1 and VT_2 (the first and second ventilatory threshold)

  • I've been busy with this for a long time today. And in the end I notice that Garmin suddenly changed the % values for the zones in the Garmin Connect app or on the Forerunner 965. This is completely insane. I don't know now if that has anything to do with my email to them (which I can't imagine). In any case, the % values in my table above are no longer what Garmin is currently suggesting again. This is a very poor performance by Garmin.

    That running and cycling are different, that it's better to measure the values (be it HR max or anaerobic threshold) accurately, I know all that. I was and am only concerned with the completely inconsistent (and constantly changing, as you can see) % values that Garmin uses.

  • It could be that the fall-back that you get when you reset your zones is something calculated from firstbeat algorithms? That would at least explain why you get different values if you keep resetting it - it might just be garmins estimation of your max hr, lacate threshold changing :D

  • When setting the heart rate zone by HR Reserve, extremely low % values are displayed.

    When you use HRR, you need to substract the resting HR from the HR before dividing by HR Max - RHR.

    if your HR Max is accurate and you use your watch for LTHR and RHR measurements, you should find out that your heart zones in BPM are quasi identical, regardless of the system you use.

  • If HR zones were properly determined for a given person then it shouldn't really matter if they are expressed as %MHR, %HRR or %LTHR. At a given heart rate the zone should be the same no matter the reference. Where it matters, I think, is when the fitness and reference change over time.

    But then Garmin defaults don't make much sense to me. The %MHR defaults are kind of standard and work for me personally in practice. When I am doing Z3 (Tempo) power training then my HR is in my Z3 (Aerobic). When I am doing Z4 (Threshold) power training then my HR is in Z4 (Threshold) zone. But then Garmin defaults for %HRR are the same as for %MHR which does not make sense to me. And for %LTHR are different, but also quite high from my perspective.

    Check out this spreadsheet for comparison (credits to Freddy):

    docs.google.com/.../edit

  • Thank you for sharing the spreadsheet. You are right that using the same % for HR Max as for % of HRR will result in different zones. 

    in my case, I just reverted to the default % using HRR and went for a threshold run. 
    After the run, I found a better match between the HR zones and the power zones (based on FTP/CP) distributions then between the standard LTHR based zones and the power zones distributions I usually see. Just an example of one.

    My take is that if you train with HR zones, using LTHR or HR Max default values is simpler and having VT1 and VT2 HR between 2 zones makes it easier to work on these thresholds (longer intervals  below or shorter just above, and over-unders and such.

    if you train with power or pace, you could switch to %HRR and you will have the thresholds within zones, capturing more of cardiac drift variations for the same effort and being closer to the % of VO2 Max system that the watch uses.

    By googling the topic you can see caes where the %of HRR is lower than with %HRMax and cases where it is the same (like Garmin’s default). Your choice.


    https://marathonhandbook.com/how-to-calculate-your-heart-rate-zones/

    You’ll notice that these target zones are a little different than those calculated with just maximum heart rate, particularly the lower zones. However, this HRR method is thought to be more accurate, especially for fit individuals.”