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Wahoo tickrx HRV

Former Member
Former Member
Hello Guys,

I just bought a Wahoo tickrx chest strap primarily for its ability to track HRV (as garmin one does)

How can I make sure that it is transmitting data correctly to the garmin unit ? And as an aside, to HRV4training since I also bought this app in the same time.

Thanks for the support !
  • Former Member
    0 Former Member
    Well TBH the one reason I also got a Tickr X was to be able to wear one HR strap when using Zwift running or cycling on a treadmill or Wattbike at my gym with an iOS device and still transmit HR to both Zwift and record on my Garmin. That said I have sometimes worn both a Garmin strap and a Tickr X so could get running dynamics as well but guess could now use the RD Pod. Training Status seems to have worked OK. You won't get VO2 Max updates on a treadmill anyway although don't think RR data is essential for that as you seem to get such updates from just OHR heart rate data.

    What are you trying to discover from the RR data that the Garmin platform does not already do so?

    Common sense suggests a company will make sure things work with its own products first and foremost and then follow standards (like the ANT+ ones) so 3rd party developers can hopefully use the data from them. There is of course the "competing" ANT+ or BLE communication protocols for devices like HR straps. Some have chosen one way or the other. You don't for instance see native ANT+ support in an iPhone nor a Polar device. Makes sense for Garmin to focus on ANT+ since they essentially own it but at least they are starting to allow BLE sensor connections although there is a big limitation with those in that you can only pair with one thing at a time so a BLE only sensor can never "work" in real time with both a Garmin and another other device regardless of who makes it.


    I don't want to discover anything in particular.

    It is just that I paid for two products and want to be sure to get value from them i.e. lactic treshold estimation for example, correct recovery advices and be able to perform HRV morning tests with HRV4training for example hence the TickrX. So I apparently need to make these checks myself since garmin don't provide a simple way to do it ... e.g. Check of R-R transmitting

    This is my first garmin products regarding the watch and sometimes I think they are lacking in explanation, in this particular area and others. For example, they don't provide formulas for VO2max depending on wheter you use %HRR, %HRmax or %Lactate Treshold which to me is quite incredible. You buy something and you don't even know what the options do.

    Apparently, from a friend who did some tests,
    formula with %MaxHR for your zones is
    Zone 1 : 0.5 * HRMax to 0.6*HRMax
    formula with %HRR for your zones is
    Zone 1 : Resting Heart Rate + (HRMax - RestingHeartRate) * 0.5 to Resting Heart Rate + (HRMax - RestingHeartRate) * 0.6 (Karvonen formula)

    Well ... You can't find this information on Garmin 935 manual and I find this quite incredible.
    Same for some HR functions e.g. Training status, Training load. You actually have to go to FirstBeat Website to find details about the functions, calculations and the scientific papers supporting the functions. This is incredible in my opinion.
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    For example, they don't provide formulas for VO2max depending on wheter you use %HRR, %HRmax or %Lactate Treshold which to me is quite incredible.


    The method (or algorithm, or formulae) by which Garmin devices estimate VO[sub]2[/sub]max is proprietary, and licensed for use from Firstbeat which owns the intellectual property. You bought a device that Garmin promises will provide you with VO[sub]2[/sub]max estimates by applying that method, but why would you expect any explanation or visibility of the nuts and bolts, as if such was your entitlement by virtue of buying a consumer IT product or appliance?

    Garmin is not going to tell you the “formulas” it uses to determine the number of steps taken on the basis of data harvested from the three-axis accelerometer, either; that is trade secret. Or how it determines the user's heart rate using data from the optical heart rate sensor. Or even the specifics of how it obtains information provided to the Weather widget on the watch. You're entitled to the utility of said features, not disclosure or understanding of the underlying technology such that you could independently validate the methods, and/or adapt, leverage or extend the capabilities to anything else you may find useful.

    If Firstbeat wants to publish and disclose its intellectual property to you independently of Garmin, that's its prerogative; however, neither company has any obligation to you to do so.

    Apparently, from a friend who did some tests,
    formula with %MaxHR for your zones is
    Zone 1 : 0.5 * HRMax to 0.6*HRMax
    formula with %HRR for your zones is
    Zone 1 : Resting Heart Rate + (HRMax - RestingHeartRate) * 0.5 to Resting Heart Rate + (HRMax - RestingHeartRate) * 0.6 (Karvonen formula)

    Well ... You can't find this information on Garmin 935 manual and I find this quite incredible.


    That is what Garmin sets by default, but the user can change the zone boundaries (expressed in terms of either absolute BPM, or percentages of some reference value). Furthermore, the FR935 Owner's Manual in actual fact tells you the Heart Rate Zone Calculations it uses.

    The manual also states, “Select %HRR to view and edit the zones as a percentage of your heart rate reserve (maximum heart rate minus resting heart rate).” Expressing HRR as (HRMax‑-‑RestingHeartRate) like you did in multiple instance would therefore be redundant. Whether there ought to be any attribution to Karvonen is an intellectual property law question, even if Garmin is indeed using the Karvonen formula, and not about making it easier for you the user to gain understanding or knowledge.
  • Former Member
    0 Former Member
    The method (or algorithm, or formulae) by which Garmin devices estimate VO[sub]2[/sub]max is proprietary, and licensed for use from Firstbeat which owns the intellectual property. You bought a device that Garmin promises will provide you with VO[sub]2[/sub]max estimates by applying that method, but why would you expect any explanation or visibility of the nuts and bolts, as if such was your entitlement by virtue of buying a consumer IT product or appliance?

    Garmin is not going to tell you the “formulas” it uses to determine the number of steps taken on the basis of data harvested from the three-axis accelerometer, either; that is trade secret. Or how it determines the user's heart rate using data from the optical heart rate sensor. Or even the specifics of how it obtains information provided to the Weather widget on the watch. You're entitled to the utility of said features, not disclosure or understanding of the underlying technology such that you could independently validate the methods, and/or adapt, leverage or extend the capabilities to anything else you may find useful.

    If Firstbeat wants to publish and disclose its intellectual property to you independently of Garmin, that's its prerogative; however, neither company has any obligation to you to do so.



    Come on. Giving me the basic formula is not trade secret. It is intellectual honesty so that I at least know what is the basis for computing it and the expected accuracy. Otherwhise I have to go myself do a lab test to measure the accuracy of garmin VO2max against lab VO2max. By the way, thanks to firstbeat data, the accuracy is around +/- 5% against lab tests.

    That is what Garmin sets by default, but the user can change the zone boundaries (expressed in terms of either absolute BPM, or percentages of some reference value). Furthermore, the FR935 Owner's Manual in actual fact tells you the Heart Rate Zone Calculations it uses.

    The manual also states, “Select %HRR to view and edit the zones as a percentage of your heart rate reserve (maximum heart rate minus resting heart rate).” Expressing HRR as (HRMax‑-‑RestingHeartRate) like you did in multiple instance would therefore be redundant. Whether there ought to be any attribution to Karvonen is an intellectual property law question, even if Garmin is indeed using the Karvonen formula, and not about making it easier for you the user to gain understanding or knowledge.


    No it is not. they just say bluntly, whatever the settings, that the zone is described as 50-60% of your %HRmax (this url)

    My formula is clearly different from 0.5*(HRR) since you need to add resting heart rate i.e. resting + 0.5*(HRR)
    No way to find that in the manual as far as I know.
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    > Come on. Giving me the basic formula is not trade secret.

    I would be astonished if it was "basic" as otherwise some clever souls would have almost certainly worked it out by now and posted it here!
    The fact you want R-R data which could be thousands of data points per run suggests you would be a while number crunching in Excel even if you did know what the algorithm is.
    But go the other way and it is "basic". Run a 5K or 10K etc etc note your time and then we can tell you what your approximate VO2 Max is. Ultimately though race times are more meaningful...
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    Furthermore, the FR935 Owner's Manual in actual fact tells you the Heart Rate Zone Calculations it uses.


    Interesting and pretty standard rules for training, is there a similar table for LTHR Pace ? That's not such a common training method AFAIK and the percentages seen in GC have me a bit confused on how they should be used : 65%, 80%, 89%, 95%, 100% of the LTHR.
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    Actually, it is not.


    Go back and reread my post. I didn't say percentages used for setting HR zone boundaries are not trade secret. I said the method for determining step count from accelerometer data, and heart rate from optical heart rate sensor data, would fall in that category. In your earlier post, you intimated that Garmin ought to explain everything it does to the user, and that's just pure unadulterated nonsense.

    The mystery remains concerning %Lactate.

    Interesting and pretty standard rules for training, is there a similar table for LTHR Pace ? That's not such a common training method AFAIK and the percentages seen in GC have me a bit confused on how they should be used : 65%, 80%, 89%, 95%, 100% of the LTHR.


    You can easily find out what Garmin use as the default HR zone boundaries (in terms of percentages) by clicking on Reset, once you've selected the basis for determining HR zones:



    Try (sequentially) specifying a few different values of LTHR and click Reset, once you've selected “% of LT” as the basis for determining HR zones. The percentages that don't change from LTHR value to LTHR value are Garmin's defaults.

    Now regarding intellectual property, I don't think Garmin sharing their formulae would cause any disadvantage to them.


    Your view is entirely irrelevant in that regard. By all means, express your view in an open, online discussion with fellow users, but don't expect anyone to treat it as worthy of consideration in Garmin's business decision making.
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    Right, that's where I got the LTHR percentages from in my previous post, what would be of more interest would be to have a similar table with explanations as the one with MaxHR percentages you'd linked above as the zones don't match up except for the 70% MaxHR and 80% LTHR. Now that's my case but by construction it seems Z3 and Z4 can't match up.
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    HR zone boundaries are entirely up to you. TBH I think you can over analyse this and I have largely stopped worrying about it. Most runs should be "easy" but throw in a regular "long" run and also maybe two or three tempo and/or thresholds runs or interval sessions per week and you won't be far off a decent training program.

    If you run 2 bpm higher or lower than your target zone it is hardly going to matter.
  • Former Member
    0 Former Member
    HR zone boundaries are entirely up to you. TBH I think you can over analyse this and I have largely stopped worrying about it. Most runs should be "easy" but throw in a regular "long" run and also maybe two or three tempo and/or thresholds runs or interval sessions per week and you won't be far off a decent training program.

    If you run 2 bpm higher or lower than your target zone it is hardly going to matter.


    I agree with you.
    I have trained for about 15 years without HR and I achieved decent results. So I totally agree with you.

    However, now that I have a tool to play with, I like to understand at least partially what is behind the hood. And I was expecting to find such information in the user manual as this could be a reason to buy the watch i.e. which formulas do they use to automatically predict your zones. Even if you can indeed manually set them, maybe I am interested in the automated way for easiness.

    I also find this a shame that you can't easily access via garmin user manual and/or website FirstBeat related articles on e.g. VO2max as they are available and back up the quality of the product. Instead, since you have to search that yourself and put together the pieces, I got at first the feeling that the tool is still a bit messy and not 100% controlled.
    Same with the tickrX. HRV works with bluetooth but you learn this information not via their website but via people who spent their own time testing the product or via a discussion with the tech board.

    Hopefully, garmin forums and tech support are very helpful and responsive.

    And I end here by saying that I am happy with the 935. It just took me some time to figure out some "details" but which for me are important as I am interested in the technology and I like to know what are the limits.
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    Exactly, every serious runner should know about the 80/20 rule and any old (GPS) HR watch will help you achieve that but if Garmin are going to be selling more info they should provide some minimal background !

    Right, that's where I got the LTHR percentages from in my previous post, what would be of more interest would be to have a similar table with explanations as the one with MaxHR percentages you'd linked above as the zones don't match up except for the 70% MaxHR and 80% LTHR. Now that's my case but by construction it seems Z3 and Z4 can't match up.


    So I found this https://mtbcoach.com/training-sessions/zone-calculator/ where LTHR is used and they have 5/7 zones...that don't match Garmin's "65%, 80%, 89%, 95%, 100%" naturally ;-)

    With an LTHR of 160 :
    HR Zone /Power Level Watts Heart Rate RPE Description
    1 104 — 130 1-2 Recovery
    2 131 — 141 3-4 Endurance
    3 142 — 149 5-6 Tempo
    4 150 — 160 7 Lactate Threshold
    5a/5 162 — 163 8 Above Threshold
    5b/6 165 — 168 9 Aerobic Capacity
    5c/7 170 10 Anaerobic Capacity