Sleep features for monitoring cumulative stress in new Polar watch

  • Creator
    Topic
  • #24262
    Michael
    Participant

    I see that the new watch from Polar has features that seem like they automate the tracking of both cumulative training stress and recovery from that stress. I’m not aware of any other device that does this. Would this be particularly useful for someone who is aerobically deficient working on ramping up volume for base training? Both to prevent burnout and to ensure I train enough rather than being lazy with avoiding overtraining as a convenient excuse.

    http://www.dcrainmaker.com/2019/06/polars-199-ignite-gps-hands-on-everything-you-ever-wanted-to-know.html/amp

    The article also mentions accurate heart rate in sprints and I’ve seen forum posts here mention concern about accuracy. Have optical sensors gotten better? Is Polar better than others for that?

  • Keymaster
    Scott Johnston on #24265

    Michael:

    I have no personal experience with this new Polar watch. I am dubious however that the predictions will be accurate. If you have not read this article you should. My guess is that Heart Rate variability is still the underlying measurement that they are using to determine recovery state. As for the wrist sensor: I’m dubious that it will be accurate enough. We’ve tested the most expensive watches from all the companies and NONE of them work well for wrist based HR. Maybe Polar has come up with a break through here but I doubt it. I would love it if this watch did the things they say. Maybe I’ll have to get one and try it. Until them I remain skeptical.

    Scott

    Participant
    Michael on #24336

    How do you explain this graph then? https://media.dcrainmaker.com/images/2019/06/image-27.png

    The only thing I really need is within 5 bpm or so to make sure I stay within zone 2. In fact, the at rest monitoring might be the most useful part since training seems to lead to an increase in resting heart rate even the following day.

    I don’t think Polar has any sort of breakthrough, I’ve just seen reviews mentions that among the wrist-based ones they are the most accurate.

    Edit: Well, I ended up ordering it… I feel like 24/7 monitoring will matter more for me than accuracy. My pulse is now 75ish even though I’m seated in a coffeeshop. Wondering if the adrenaline-inducing portion of my ride yesterday (very technical descent) slows recovery.

    Participant
    death.jester on #24358

    My observation with two watches with wrist heart rate (Forerunner 235 and Fenix 5+) shows that the problem with the wrist heart rate is not the “absolute” accuracy when, e.g., running with a roughly constant pace, but the delay when my heart rate rises. What I mean is, fast heart rate changes, such as very short spikes (when, e.g., climbing, weight lifting or doing interval training with short intervals) are just not recognized by the wrist heart rate sensor. Here I have two examples:

    With chest heart rate strap:
    https://connect.garmin.com/modern/activity/3663552483

    With the optical sensor from the watch:
    https://connect.garmin.com/modern/activity/3636127880

    it’s both indoor climbing and I’ve just tracked it for fun. But anyway, you see on the elevation graph that the watch recognized the “altitude” change even indoors (which amazed me). But you can then easily correlate whenever I was climbing, because my heart rate went up, whereas on the one which I tracked with the wrist sensor you see nothing. Also the summary below shows 107 – 176bpm (when measured with the chest heart rate strap) vs. 87 – 118bpm (when measured with the optical sensor). Of course these were two different sessions, but I’m pretty sure my heart rate in the second session was above the given value.

    And as you can see from both graphs, by “short intervals” and “fast heart rate changes” I mean roughly 1.5-2 minutes, which is a lot! Especially, when the experts here (Scott and Steve) are talking about “do an interval of 8 seconds” xD

    Moderator
    Scott Semple on #24363

    As @death-jester described, the problem with wrist monitors is one of accuracy versus precision.

    On long steady-state activities, the accuracy is probably sufficient. The measured average is probably pretty close to the true average. From the simul-comparisons that I’ve done, the average heart rates of chest straps versus wrist opticals are very close.

    But the precision of wrist opticals (defined by how quickly they can react and record second-to-second changes in HR) are horribly imprecise. So imprecise as to be useless.

    For example, if a long steady-state activity has an average HR of 140, and if a very stochastic activity has an average HR of 140, a wrist-based monitor won’t be able to reliably measure the difference nor the training impact of the latter. A chest strap will. (The idea of normalized power is very similar.)

    If your training is important to you, why wouldn’t you want both accuracy and precision at all times?

    Participant
    Michael on #24376

    Well I’m planning on using it mostly for base training so I think not knowing the spikes will be ok as long as I’m mindful to minimize any sudden changes in effort. Training is not important enough to me to use multiple tools and spend time piecing together different sets of data.

    I’m probably a lot less serious than most of the people on this website. I just want to get my aerobic capacity high enough that I can do the things I enjoy all day rather than only for a few hours. I was at that state a few years ago with zero mindfulness around training, so just the intention to focus on base-building and knowing that is what I need should be enough to reach my goals.

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