Heart rate sensor Apple Watch 3. Are these false readings?

Discussion in 'Apple Watch' started by Goodeys, Oct 19, 2017.

  1. Goodeys macrumors newbie


    Oct 19, 2017
    Hi all
    Just looking for some clarity on the heart rate data. Mine seems to occasionally be all over the place. For example this morning my heart rate went from 71 to 172 to 120 to 72 and there are 5 different readings all from the same minute and whilst sitting down. Has anyone else noticed the Apple Watch do this? Or should I get myself to the drs?! This happens a few times a day. Last night it went from 46 to 102 back to 49 all in the space of a minute.
    Any advice greatly received.


    Attached Files:

  2. itegypt macrumors 6502a


    Aug 6, 2011
    I don't own the latest apple watch but I have had this with an older watch os so check for iphone/watch software upgrade and if you are up to date you may restart your phone/watch and check again
  3. honglong1976 macrumors 65816


    Jul 12, 2008
  4. Mercenary macrumors 65816


    Sep 17, 2012
    If your watch recorded a rate of 174 during no workout then you will most likely have felt this. Your heart will feel like it's pounding out your chest.

    That said I've found the heart rate sensor to be pretty accurate.
  5. newellj macrumors 604

    Oct 15, 2014
    Boston, MA, US
    I've compared my S3 to readings from various other devices that are known to be very accurate, such as Mio Slice and a Polar H7. They're all right on. If you're getting readings that inconsistent, have you looked at how you're wearing the watch? I get goofy readings if the watch isn't pretty snug, and it needs to be up somewhat from your wrist.
  6. zhenya macrumors 603


    Jan 6, 2005
    You would know if your heart was at 170+ BPM.

    The AW HR monitor is pretty good, but it still gives a lot of bad readings like every wrist-mounted device. During my runs it typically takes 1.5-2 miles for the readings to settle in - up until that point they are typically 170+ - same as my Garmin wrist monitors - and not at all accurate.
  7. PinkyMacGodess macrumors 601


    Mar 7, 2007
    Midwest America.
    There are some people that the optical method for determining heart rate just doesn't work, or work consistently. You also have to consider the sensor placement. I've gotten skittish stats from it from time to time. I thought '172? I got a reading of 220 one morning. And that was without coffee!'. It happens... One morning I got a 120-ish reading, and it WAS beating at 120-ish! :eek:
  8. Mad Mac Maniac macrumors 601

    Mad Mac Maniac

    Oct 4, 2007
    A little bit of here and a little bit of there.
    I'm confused... How did you manage to get such continuous HR readings during non-exercise activities? Is that a default feature on Series 3 that I'm unaware of? I'm assuming you do NOT have an external HR monitor hooked up...

    Regarding your question, I also get similar anomalies from time to time. Not exactly helpful, but it's true.
  9. srshaw macrumors 6502

    Aug 13, 2011
    I get this. I'm not sure the aw is expecting low heart rates. I often click on mine and it will tell me 106 or something, and then falls to a correct 53. Doesn't usually go back up though.
  10. apolloa macrumors G4

    Oct 21, 2008
    Time, because it rules EVERYTHING!
    The built in optical sensors are not as good as a chest strap etc, but they are pretty good for something built in, mine goes up when I exercise and then stays stable in the day and drops when I sleep, don’t think I’ve hit 170 bpm though?

    If you haven’t done so, ask someone else to wear your watch for a day and see what it records then?
  11. BigMcGuire Contributor


    Jan 10, 2012
    I can definitely tell when my heart rate is 120+bpm.

    I had one HELL of a nightmare one night and woke up to my watch notifying me about my heart rate. But this only happened once (I get these once every few years).

    Haven't had it happen while I was awake, ever. My Scosche Rhythm+ and my AW3 are usually spot on with each other. One just gets my heart rate a lot better when I exercise without having to tighten the band.

  12. Newtons Apple macrumors Core

    Newtons Apple

    Mar 12, 2014
    Jacksonville, Florida
  13. v3rlon macrumors 6502a

    Sep 19, 2014
    Earth (usually)
    I have gotten some 'flyer data' on my 1st model watch. Often the first reading when asked to measure will be substantially off.

    BUT- I had an instance of AFIB a couple weeks ago. I had no idea what was going on, but I knew it felt like my heart was pounding. The Apple watch said I was around 140 bpm. I got in to see a doctor. The little finger clip they always use reported 70 bpm. After some talking, they put me on an EKG and the watch was in lock step with those readings. I spent several hours on an EKG that day, and the watch stayed pretty close most of the time (within 5 bpm which is good enough for margin of error given the time lag).

    This was the most accurate reading including the blood pressure cuff I also spent the day in.

    So for me, I would say the watch is pretty darn good. Others have had issues. There is the question of how snug is the band and some people report sweat can cause iffy readings.
  14. Robejazz macrumors member

    Jun 14, 2013
    Couple of questions:

    1. Which App is that? Looks good
    2. How do you like the Rhythm + with the Apple Watch and how do you use it?

  15. BigMcGuire Contributor


    Jan 10, 2012
    The app is HeartWatch. I really like it though I don't use it all that much - but I'd definitely recommend it for the data it provides. I can see my average overall heartrate over the month.

    My coworker sold me a new-in box Rhythm+ for less than half of new price so I couldn't pass it up. The AW does a pretty good job of getting my heart rate unless it's below freezing outside and/or I've been sweating like crazy - the Scosche Rymth+ works all the time - and after using it for awhile, helps reduce the battery drain on the AW while exercising. Have to find a sweet spot on your arm or you'll get weird readings (at least on mine) every now and then that you have to go into Apple Health and delete (like a 32,000 heart beat) - also, I have to open heart rate on the watch for it to connect to the Rythm+. But I'd recommend it. Because I have it I can wear the AW a little looser and not have to save the back of my wrist (I'm very hairy).
  16. helveta macrumors regular

    Mar 31, 2012

    I got my AW3 last november and was alarmed that I was during a long hard run I could see readings that were in the 190's for extended periods and could spike up to over 220. I didn't think they could be right so I got a wahoo chest strap heart rate monitor and always wear that to exercise now. Now I warm up, don't take it quite so hard and try to keep my heart rate in the 130-150 range but I can still get spikes quite a bit higher. This image is actually from a body weight strength training day.

    I'm 60yo and my resting heart rate is usually around 60 +/-. I don't know where that 39 bpm came from.

    Anyway, I'm not sure what to make of any of this heart rate stuff.
  17. dwsolberg macrumors 6502a

    Dec 17, 2003
    It might be something, or it might just be spurious readings.

    My Apple Watch sometimes gives bad readings. For example, sometimes I can be on the StairMaster with a heart rate around 132 (according to the StairMaster heart rate sensor), but my Watch will say that I’m at 204 or something like that. And it goes both ways, sometimes I’m running fast at a heart rate of 170, but my watch will say something like 56. The watch is usually very accurate, but for me at least, it can put out some bad readings.
  18. rdavis41 macrumors regular


    Jul 10, 2009
    I've been using a Polar H10 Chest Strap but hear great things about the Scosche. Quick question, do you wear it on the same arm as your Apple Watch or opposite one?

    I LOVE the Heart watch app. I highly recommend people download the Autosleep and HeartWatch app. It is great for sleep tracking and the closest to Fitbit's sleep tracking I've found. I've changed my diet around these past few weeks and have realized the impact coffee has been having on my sleep and heart rate thanks to the apps.
  19. BigMcGuire Contributor


    Jan 10, 2012
    I've been wearing it on the same arm as my Apple Watch - I've done it on the other side but it's kinda easier to just have everything on one arm. I've had it for awhile now so it's second nature to put it on before a run, turn it on, open Heart Rate on watch, then start up an Activity.
  20. Newtons Apple macrumors Core

    Newtons Apple

    Mar 12, 2014
    Jacksonville, Florida
    Next time you see these crazy readings, just stop and count your pulse for 15 seconds and multiply by 4.

    Most people will notice something if their HR is in the 200-220 range.

Share This Page

19 October 19, 2017