Exact watch placement for proper HR monitoring

Discussion in 'Apple Watch' started by mama2twoboys, Jun 15, 2015.

  1. mama2twoboys macrumors newbie

    mama2twoboys

    Joined:
    Mar 9, 2015
    #1
    Does anyone know where the watch should be placed on your arm for proper HR monitoring while exercising? Or maybe anyone else experiencing these problems?

    During exercise, I'm having the problem of my watch losing my HR. I'll look down and it's 160, and it's 71 thirty seconds later... mid exercise. Really beyond irritates me. (crossfit, HIIT, cross training type work outs)

    I've tried tightening the band, loosening the band, and nothing seems to help.

    I wear the watch about 1/4 inch above my wrist bone (toward the elbow). I have small wrists, and a very bony arm so I can't really place it closer to my hand.

    Thanks!
     
  2. MaulRx Suspended

    Joined:
    Aug 27, 2012
    #2
    They haven't been clear on how tight and where to wear the watch. The two black and white images are ambiguous. That's probably because it's different for every person. Maybe it's defective?
     
  3. mama2twoboys thread starter macrumors newbie

    mama2twoboys

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    Mar 9, 2015
    #3
    Thanks, yes I have wondered if something is wrong with it. A few of my friends have never had that problem.
     
  4. kirkhuffy macrumors regular

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    Oct 1, 2012
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    Philadelphia
    #4
    I wear my watch just above my wrist bone bump. For the sport band I am on the third hole from the bottom on the smaller strap. I can easily slide my finger between my wrist and the band but it still fits snug. When I work out I tighten it by one hole. I have yet to not get a pretty damn accurate heart reading when I look at it.
     
  5. Smurphy Gherkin macrumors regular

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    Apr 13, 2015
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    Melbourne, Australia
    #5
    Good luck finding a good spot. There are major arteries either side of the normal position you wear a watch, but I tried manually holding it there, and saw no difference in accuracy.

    Compared to a fingertip, or a electrical chest strap, wrist monitors are a harder gig.
     
  6. Julien macrumors G3

    Julien

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    Atlanta
    #6
    One notch tighter than I normally wear and moved up the wrist slightly. I always wear a Garmin 620 too and the :apple:Watch is almost always correct when worn this way. Unbelievably accurate for an optical sensor.

    [​IMG]
     
  7. dandrewk macrumors 6502

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    Apr 20, 2010
    Location:
    San Rafael, California
    #7
    What exercises are you doing when the heart rate numbers go weird? If it's anything that will constrict blood flow through the wrist, e.g. lifting/holding weights, push ups etc., then there's nothing you can do about it. It's the nature of any heart rate monitor that measures beats via the wrist.
     
  8. NovemberWhiskey macrumors 68030

    NovemberWhiskey

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    May 18, 2009
    #8
    Geez that's tight.
     
  9. Newtons Apple macrumors Pentium

    Newtons Apple

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    Mar 12, 2014
    Location:
    Jacksonville, Florida
    #9
    It will vary from one person to another. The sensors just need to be held against the skin and if you are wearing you watch loose, you might need to tighten a bit while doing exercise. The sensors are looking for pulsing capillaries and not an artery.
     
  10. Newtons Apple macrumors Pentium

    Newtons Apple

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    #10
    Looks tight to me too!
     
  11. susan12369 macrumors 6502

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  12. Julien macrumors G3

    Julien

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    #12
    It is slightly but when running I don't notice it. Endorphins take over. When weight training I leave it in my 'normal' rest of the time hole.

    Also I have externally low body fat so it probably looks tighter than it is.
     
  13. mama2twoboys thread starter macrumors newbie

    mama2twoboys

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    Mar 9, 2015
    #13
    Yep, guess it's the arm constriction. It's mainly a cross training / cross fit type stuff. Ropes, push ups, weights with arm movements.

    Guess it's time to find a chest strap!

    Thanks
     
  14. jkun macrumors member

    Joined:
    Jun 24, 2012
    #14
    I have similar problems. Wrist sweat is also a contributing factor I think. Especially when working out, I think the band has to be on super tight.
     
  15. Fiestaman macrumors regular

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    Feb 7, 2009
    #15
    Weird. Capillaries have continuous flow and thus no pulsations. I thought it used photoelectric diodes to measure variations in green light absorbency (or red using infrared) to determine changes in blood flow that result from the rhythmic beating of the heart.
     
  16. Newtons Apple macrumors Pentium

    Newtons Apple

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    #16

    Sorry but that simply is not so. Blood might slow down between pulses in the cappilaries but the speed of blood flow pulses with the HR.

    What do you think the light sensors are looking at for blood flow on top of your wrist?;)

    These type devices use light to track your blood by illuminating your capillaries with an LED. The blood passing through the capillaries IS in a pulse and this determines the heart rate or pulse.:cool:
     
  17. Julien macrumors G3

    Julien

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  18. Fiestaman macrumors regular

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    Feb 7, 2009
    #18
    They are looking at the flow through arteries. The only things with intermittent flow. In this case, I'd suspect they're looking at the posterior interosseous artery or one of its branches. You are correct that they use light to track flow, but completely and utterly wrong in saying they track the flow through capillaries. Capillaries are only one cell thick and have continuous flow making them an impossible target.
    You need to brush up on your cardiovascular physiology if you honestly believe capillaries have intermittent flow. Vascular resistance at the arteriolar/capillary junction causes blood to pool prior to capillaries so there is a constant supply of blood to be allowed into the capillaries. The heart beats to add blood to junction, vascular walls around junction expand, in response, to allow room for the new blood and prevent pressure from rising. Then they constrict the vascular walls while heart is not beating to keep pressure from falling and to force blood into capillaries. This keep a constant blood flow through them. Autoregulation at its finest.
    Think of it like this. In order for you to have a pulsation, one would need a variation in pressures, like when you measure your blood pressure. Systolic is max and diastolic is minimum. Blood flows during ventricular systole and doesn't through diastole. It is this variation that causes the pulsation. Capillaries have a constant pressure and thus no pulse.
    Capillaries are like soaker hoses that you use in the yard. Try and measure a pulse there. It's continuous and your capillaries work the exact same way.

    Source: Masters of Science Medical Sciences
     
  19. Newtons Apple macrumors Pentium

    Newtons Apple

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    #19
    Sorry but the arteries are on the other side of the wrist. The AW light is searching to the pulsed blood at the capillary level.
     
  20. Fiestaman, Jun 23, 2015
    Last edited: Jun 23, 2015

    Fiestaman macrumors regular

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    #20
    Sorry but you're still spewing misinformation. There are multiple arteries on the back side of the wrist or the posterior aspect. That's why I mentioned the posterior interosseous artery which is exactly where the heart rate sensor rests on your wrist. I have no idea how you're arguing against the facts of science laid out in front of you. THERE IS NO PULSE AT CAPILLARIES. End of story. Read up on cardiovascular physiology. You'll learn a lot and won't spread misinformation.

    Video showing the continuous flow through capillaries. What's the pulse there?
     
  21. Newtons Apple, Jun 23, 2015
    Last edited: Jun 23, 2015

    Newtons Apple macrumors Pentium

    Newtons Apple

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    #21
    Just a one minute search I found this:

    By illuminating your capillaries with an LED, a sensor adjacent to the light measures the frequency at which your blood pumps past (aka your heart rate). Moments later, you've got a BPM (beats per minute) reading.:p
     
  22. Fiestaman macrumors regular

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    Feb 7, 2009
    #22
    I'd love to see what your source is because that's flat out wrong. Any idiot can put incorrect stuff online. Fact of the matter is that flow in capillaries is continuous so no, you can't do that.
     
  23. CobraPA macrumors 6502

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    Mar 12, 2011
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    Lansdale, PA, USA
    #23
    Really need to quote a source. This sounds like a marketing description that uses 'capillaries' to represent any type of blood vessel.

    Probably not a real description. "Moments later...." :p Seems like my AW takes more than moments for a reading most times.
     
  24. Newtons Apple macrumors Pentium

    Newtons Apple

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    #24
    Sorry just Googled it and it was one of the first things that came up with exactly how I was told it worked.

    I am not trying to convince anyone, but thanks for the suggestion
     
  25. Fiestaman macrumors regular

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    Feb 7, 2009
    #25
    Whomever told you that's how it works simply doesn't understand physiology or medical technology. I happen to specialize in both.
     

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