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Stress calculation accuracy

Josh
over 2 years ago

So I have had my epix for a few months now and i have really paid attention to my stress glance. I am extremely tired today because i didn't get that great of sleep lastnight.

What's odd is I can't really get a good fix on how my stress widget works. Yes, I know it's based on HR but what is weird is that I sat on my massage chair for a god 15 minutes. I looked at my watch said I was 95% stressed. As I was sitting on the massage chair I closed my eyes and almost felt like I could fall asleep. 

I have my watch pretty snug so maybe the vibrations are throwing off the measurement? I am just curious if anyone has tested the "stress" indicator and how accurate of a representation it is of how stressed your body is. I have watched the quantified scientist guy on youtube (and yea you don't need to mention your opinions on him, I have read the other thread where people said their comments)

Anyone have any studies or research on the accuracy of this? I am just really curious how accurate it is. 

So far today from not doing anything (purposely, I am off today and not feeling greatest due to an antibiotic im taking) I have laid in bed watching a movie almost falling asleep, the massage chair, sitting on the couch, it seems my stress has been really high the entire time.

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  • 0 over 2 years ago

    Did you take a look at your pulse, was it high to compared to what it usually is?. Without knowing exactly how Garmin have chosed to implement their stress level algorithm, I guess that they look at your average historical pulse at rest, and then compare it with your current pulse to get the stress level 

  • 0 over 2 years ago in reply to SETM

    Pulse was nothing spectacular. 73 avg

  • 0 over 2 years ago
    Josh said:
    I know it's based on HR

    Stress measurements are based on HRV and HR (IIRC) so can be a bit challenging to be measured during the day. This is the First Beat paper that discusses the measurement of all-day stress.

    Josh said:

    As I was sitting on the massage chair I closed my eyes and almost felt like I could fall asleep. 

    I have my watch pretty snug so maybe the vibrations are throwing off the measurement?

    Could very well be the case.

  • 0 over 2 years ago in reply to Dr Phil
    Dr Phil said:
    This is the First Beat paper that discusses the measurement of all-day stress.

    Can you share please?

  • +1 over 2 years ago
    Josh said:
    Anyone have any studies or research on the accuracy of this

    To start with, the accuracy we are talking about is the accuracy of measuring HRV with a wrist PPG sensor, during daytime activities. It is not specific to Garmin devices, but to all devices using PPG from wrist sensors.

    "HRV measures showed satisfactory accuracy in seated rest, paced breathing, and recovery conditions but not in dynamic conditions, including speaking. Accuracy was diminished by wrist movements, cognitive and emotional stress, nonstationarity, and larger wrist circumferences."

    https://pubmed.ncbi.nlm.nih.gov/31332802/

    Not only HRV measurement is challenging from the wrist, except maybe during no-movement sleep conditions, but it is also a set of metrics sensitive to several factors:

    High Altitude
    Illness
    Medication
    Jetlag
    Lack of sleep
    Adaptation to hot climate
    Hard training session or race performed late in the evening
    “Hangover”
    Work-related stress factors
    Social stress factors
    Emotional stress factors

    https://assets.firstbeat.com/firstbeat/uploads/2015/10/white_paper_recovery.pdf

    Given these challenges, I think these values can be taken as face value but should only be interpreted in the context of individual trends rather than in-the-moment absolute values, massage chair or not.

  • 0 over 2 years ago in reply to Josh

    In my experience, stress is accurate enough to be taken into consideration. It correlates well with my status after say a big workout, or some underlying illness.

    It is show mid/high stress then I update my training expectations accordingly.

  • 0 over 2 years ago

    for sleep and stress - always look at your sleep score breaddown - but ideally it shoudl be clear during the evening, but there are loads of factors that others have pointed out that can impact your HRV (and hence your stress). From the looks of it your sleep was pretty impact. The idea for sleep is to try and identify the reasons as to why the stress is up - did you eat/drink less than 2 hrs prior to sleep - if so what - for example if I have any alcohol it impacts my stress levels about 20mins after drink and can leave impact up to 6hrs post drinking -one drink during evening, stress is up and sleep score is down. Note that you also could be coming down with an illness - as stress is impacted by this, but then so is if your body is overtrained (though normally find that this is also reflected with a strained training status - once HRV Status is up and running).

    All day stress - loads of factors - for me its more about looking at the trend and how it varies from that, but you have to be careful, as the all day stress also includes your sleep period, if your sleep is trashed due to stress, then your average for the day is going to be high, so I also find it useful to check and see if there were patches of rest, or high high the stress patches are or if consistent - as can help to indicate if potentially indicating illenss/potential injury (over straining body).

  • 0 over 2 years ago

    Have a look at what you was eating, sugar and junk food cause high stress