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Everything is wrong with my 935

spike2205
over 7 years ago
EDIT: Solved. See post #9

First it was the lactate threshold problem :
https://forums.garmin.com/forum/into...low-heart-rate
This started with firmware 7.10, that is before updating to 7.60

Then the problems multiplied. Last Friday I did interval training. When I finished I was very surprised to see my vo2 max skyrocketing from 47 to 49 (!!!). Two days later, after my long run, vo2 max went up to 50 (!!!), and finally two days ago to 51 (!!!) after my easy run plus strides. At first I was very happy to see my vo2 max going up, but I was clueless, and after the second update of vo2 max I began to worry. I then realized that no matter how many hours I was running, no matter how hard, the training load wasn't going up as it should, but down as if I was not working out at all ! Then I figured that this decrease in training load had something to do with the vo2 max increase.

Today I had 10k easy, but I decided to go a little bit harder than this, at about 80 percent of maxHR. Even though I did so, at the end of the workout the was no performance condition at all, and the aerobic training effect was just 1.0 (!!!).

As I'm reading a lot of people have many problems, similar to mine or not, I don't know what to guess, is it a firmware problem or not ?

Could a master reset solve the problem ?
  • 0 over 7 years ago
    Ok, just did the test with the auxiliary heart rate app, the result is below. As you can see the readings are pretty much the same both for the OHRM and the strap HRM, if you exclude a small deviation at the beginning of the workout. But the pace today was easy to moderate, so it remains to do the test again next Friday, on the interval training. If it's the same again, this would mean that OHRM works fine for me.ciq.forums.garmin.com/.../1305112.png
  • 0 over 7 years ago
    Spike,

    Thanks for the update - this suggests that the HR data quality is OK.

    One of the things that happenned with the 7.60 firmware update is that for quite a few people, the watch seemed to pull some pretty funky HR zones over from GC, especially if you were using sport-specific zones. This in turned played havoc with time in zones, Training Effect, Training Load and a number of other metrics.

    I'd recommend deleting any sport specific zones, and re-establishing your zones (including your MaxHR) from scratch.
  • 0 over 7 years ago
    Ok, just did the test with the auxiliary heart rate app, the result is below. As you can see the readings are pretty much the same both for the OHRM and the strap HRM, if you exclude a small deviation at the beginning of the workout. But the pace today was easy to moderate, so it remains to do the test again next Friday, on the interval training. If it's the same again, this would mean that OHRM works fine for me.


    I have a few questions about this:

    1) What was this workout?
    2) What Chest strap did you use?
    3) That early reporting is not a small deviation, that about 10 mins when the OHRM went walkabout
    4) While in the ballpark for the majority of the workout, the OHRM either under or over compensates (just by eyeballing it)
    5) One test doesn't mean much


    Workout included: (Upper body weight training)--so lots of Muscle Flexion. Used Auxiliary heart rate (Elevate OHRM, HRM-Tri)

    Also, expand the HR data for the OHRM and pull up the Auxiliary as the overlay. In many cases they were upwards to being 60BPM apart (WrOHRM)

    https://connect.garmin.com/modern/activity/2480237750



    Again, one workout means nothing. But time and time again this happens.



  • 0 over 7 years ago
    I have a few questions about this:

    1) What was this workout?
    2) What Chest strap did you use?
    3) That early reporting is not a small deviation, that about 10 mins when the OHRM went walkabout
    4) While in the ballpark for the majority of the workout, the OHRM either under or over compensates (just by eyeballing it)
    5) One test doesn't mean much


    Workout included: (Upper body weight training)--so lots of Muscle Flexion. Used Auxiliary heart rate (Elevate OHRM, HRM-Tri)

    https://connect.garmin.com/modern/activity/2480237750



    Again, one workout means nothing, but every stress test done in labs shows that Wristbased OHRM cannot keep up with a chest strap.






    Hang on there, can you at least link to a type of workout the watch was primarily designed for? Maybe a run or a ride or a swim? I would put weight-training in the same category as I would cycling - that being you are much better off wearing a chest-strap for it. On the bike, you change hand positions on the bars and the vibrations wreak havoc. With weights, your arms are in motion, your wrists are moving, and the watch is all over the place. It's all very different than running.

    Running - for me, I find the 935's wrist-based sensor tends to be generally consistent with HRM-Tri. I say generally because it tends to fall apart with interval workouts.
    Riding - I use my HRM-Tri per above.
    Swimming - I use the HRM-Swim.
    Activity Monitoring - I use the watch. Seems to be fine.

    Based on what I am doing, I have much different expectations.
  • 0 over 7 years ago
    link to a type of workout the watch was primarily designed for
    AFAIK there is no specific workout that optical HR was designed for. It's designed to measure heart rate by looking at the change of colour that occurs each time blood pulses through a superficial vein. What we know, is that when things get 'active, or there are differences in skin colour, hair, temperature (veins go deeper in the cold) and sweat, optical HR becomes less reliable and leas able to produce valid numbers.

    All this is moot, however. Optical, wrist heart rate detection works for some, it doesn't for others. And even for those for whom it works, when things get 'active' it become less than reliable. In the main, if you want better reliability (works more often than not), better validity (measures what it's meant to measure), a chest strap ticks the boxes far better than WHR does.
  • 0 over 7 years ago
    I have a few questions about this:

    1) What was this workout?
    2) What Chest strap did you use?
    3) That early reporting is not a small deviation, that about 10 mins when the OHRM went walkabout
    4) While in the ballpark for the majority of the workout, the OHRM either under or over compensates (just by eyeballing it)
    5) One test doesn't mean much


    Workout included: (Upper body weight training)--so lots of Muscle Flexion. Used Auxiliary heart rate (Elevate OHRM, HRM-Tri)

    Also, expand the HR data for the OHRM and pull up the Auxiliary as the overlay. In many cases they were upwards to being 60BPM apart (WrOHRM)

    https://connect.garmin.com/modern/activity/2480237750



    Again, one workout means nothing. But time and time again this happens.





    1) Running
    2) An old Garmin HR 7295
    3) If it was so for all the workouts I wouldn't mind. But it isn't as it seems below
    4) it seems to me you're looking for needles in the haystack with this. Again, if the deviation was so minor, a beat up or down (for the majority of the workout as you say, leave the beginning out), I wouldn't mind at all. Heck, if you take two same chest HRMs from the same manufacturer, same model, same batch and all, and put them in the same person, don't expect to have 100% same readings. How do you expect this from two different technologies? And to be devil's advocate here, how do you know it's the OHRM that deviates and not the chest strap? Again, I'm saying, all this would be the case IF the readings were similar for all the workouts, and to be more specific here (sorry that I wasn't before) when I say all the workouts I mean all running sessions, I bought this watch primarily for running and secondly for cycling, definitely NOT for weight training, RIZKNOWS always says it in his reviews, OHRMs are NOT good for weight training,... so if this was the case I wouldn't mind, BUT...
    5) 5.5k tempo today, threshold pace or above, I decided to do the test today instead of Friday's Interval training. It was cold outside today and very humid, it was raining till early morning. Don't know if these conditions affect the OHRM result but the deviation today is more than obvious. I could see it on the watch as well during the workout, I created a screen for both HRMs and the readings were different for the majority of the workout.

    You can see the workouts here :

    https://connect.garmin.com/modern/activity/2477055596 (the previous one)

    https://connect.garmin.com/modern/activity/2481465821. (Today's workout)

    ciq.forums.garmin.com/.../1306186.png
  • 0 over 7 years ago
    All this is moot, however.


    What is moot? I stated my experience with the 935’s optical sensor. The fact of the matter is you can have problemaic data with a chest strap as well. Like when the strap needs 5-10 minutes to stabilize and find your actual HR at the start of a run. See attached. Neither is perfect. Both have limitations. Just take those limitations into account before you walk out the door.
  • 0 over 7 years ago
    Let's put this in context eh?
    All this is moot, however. Optical, wrist heart rate detection works for some, it doesn't for others.

    And goes on to say
    if you want better reliability (works more often than not), better validity (measures what it's meant to measure), a chest strap ticks the boxes far better than WHR does.


    I've found during years of using heart rate straps that the key to good performance is a thorough wetting before putting them on. This is particularly easy with the newer fabric straps. A good soaking in (warm) water before use all but does away with any problems at the start of a run. Simple physics really. Electricity travels better in wet than dry.
  • 0 over 7 years ago
    snip


    Thank you clarifying, I just wanted to know for context. Which is why I also recorded data and posted for info. A few things:

    How do you expect this from two different technologies? And to be devil's advocate here, how do you know it's the OHRM that deviates and not the chest strap?

    The chart is color coded...
    It was cold outside today and very humid, it was raining till early morning. Don't know if these conditions affect the OHRM result but the deviation today is more than obvious. I could see it on the watch as well during the workout, I created a screen for both HRMs and the readings were different for the majority of the workout.
    Not trying to be condescending sounding here; but read a bit about the shortcomings of OHRM in general (scroll up for the Valencell write-up I posted). Long story short: Cold weather is bad for OHRM. Not just Garmin, ALL are affected.
    RIZKNOWS always says it in his reviews, OHRMs are NOT good for weight training,... so if this was the case I wouldn't mind, BUT...
    I like RIZKNOWS too, but he's not alone. I think nearly every reviewer ever states this with OHRM.
  • 0 over 7 years ago
    What is moot? I stated my experience with the 935’s optical sensor. The fact of the matter is you can have problemaic data with a chest strap as well. Like when the strap needs 5-10 minutes to stabilize and find your actual HR at the start of a run.


    Issues found with chest strap:

    ~The strap is old
    ~The batteries are near dead
    ~The Electrodes have not been wet (which every Chest Strap owners guide tells you to do this before a workout) Example: http://www.manuals365.com/swf/garmin...12.html?page=2

    Now we can debate all day long about how to do so. You could warm up and build up a sweat before using the strap for an activity, you can put soak the strap, you could use electrode gel. Personally I use the gel, just pea sized dab and it's good. That stabilizing effect is again human error because the electrode most likely was not moisened. That's not my opinion, that how they just work.

    Neither is perfect. Both have limitations.


    Let's take this into consideration because sure, their are limitations....but those limitations are not really comparable. Both literally read the beats of your heart differently.

    Chest Strap:
    ~centralized around the heart
    ~Uses electrical signals like a ECG (so literally reading your BPM in real time)

    Issues:
    ~Must wet the electrodes for best connection
    ~Chest placement isn't all that great for women (moves off the body more so than for men get erroneous reports)
    ~Electrodes wear down over time which can begin to erode reporting. Normal life span can be about a year before needing replacement (Max I ever got was a year and half)

    OHRM
    ~Worn on wrist or bicep/forearm
    ~uses multiple led's to read the blood flow under the skin. Is not reading your actual heart beats (primary), nor is it reading your pulse (secondary); it is guessing your heart beats based on the blood flow under your skin (Tertiary)

    Issues:
    ~The OHRM is gathering the report form either wrist or Bicep/Forearm. While not reading the actual beat, blood flow takes a few seconds to be delivered to the area of the body. Code written into the algorithm takes this into account; still it will lag behind.
    ~Skin pigment (dark skin) have been reported to not work with OHRM. Tattoos also play a factor. Arm hair has been reported to affect it, but that may or may not be an issue anymore.
    ~Tightness of band is an issue. Too tight and the led's can't pick up your blood flow (you're smushing it and potentially cutting off blood flow). Too loose and ambient light ruins the reading. Some companies use a yellow led to help offset this (Garmin doesn't)
    ~Cold weather greatly affects OHRM due to blood flow being restricted in the skin.
    ~Muscle flexion disrupts the signal. Blood flow is either restricted in the area, or the actual sensor moves too much to establish a proper reporting.

    Take into considerations the things Phil wrote and add in the issues listed above. Let me be clear; you're talking to someone that really would like OHRM to be the only thing I need for exercise; any and all of them, and not have to be concerned if it actually is giving me back accurate information. I'm choosing to do this of course, but for example when I go for a run I am wearing:

    Chest strap
    Stryd footpod
    Garmin Tempe
    Forerunner 935
    Wireless headphone
    Phone

    I'd love to just have the watch and have it do all the things the external sensors are giving me and be just as accurate, and not feel like i've just become a member of the Borg while running. So I get it, but it's not there yet if you going for accurate all the time in every situation. I don't know if it will ever get there (at least in the HR reading). This isn't my feelings on it; every report states this, ever study talks about it. Reviews alike state it. It's not Garmin, it's the whole system. Has it gotten better? Yea, I guess, but if a chest strap is going to record accurate over 10 workouts (varying types of work) and the OHRM can only get half of those accurate...i'm going to stay with the strap.

    I have no vested interest in convincing you, and i've spent enough time on this thread. All I can do is point to the things I know and what i've learned and hope it helps you, that's all.