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time heart rate readings are fluctuating and erroneous

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  • time heart rate readings are fluctuating and erroneous

    Hello again. I wanted to comment on something that's wrong with my heart monitor. In my exercise, at any given time heart rate readings are fluctuating and erroneous. Could be static electricity produced by the friction of my shirt with the band synthetic heart and body during exercise? I reached this conclusion because I have noticed that when you rub my fingers heart band readings are very high. I would like to tell me about your experiences
    Last edited by alvadom; 09-13-2009, 04:55 AM.

  • #2

    I'm sorry to hear that's happening.

    What type of activity are you doing when this occurs, such as biking or running? Also, have you tried wearing a tighter shirt? If so, did this make any difference.

    Are you using our regular heart rate monitor, or our new premium soft strap heart rate monitor?



    • #3
      Heart Rate Monitor Flucuation


      I ran today and for the first fifteen minutes or so the HR looked fine, then it sky rocketed up into the 180s with no change in speed etc. This has happened several times. There is no one else around, I was not near any places that would mess it up. I did have my footpod on, and my chest strap is the premium strap. I was also wearing a 100% polyester shirt if that is a factor.

      I really would be interested in a solution to this other than wearing cotton (I am a sweater).

      This has happened on other occaisions, but today I was purposely running slow to stay under a certain HR and my 310XT was no help.


      • #4

        You may want to try to reposition the heart rate monitor on your chest. Or, I have talked to some people who receive more accurate data with the heart rate monitor's contacts worn on their back.

        Also, please make sure that the heart rate monitor is worn tight, but not so tight it is uncomfortable.



        • #5
          We've had/have Fr305s, Edge 305s and now FR310Xts and seen this with all of the devices, particularly when wearing loose flapping shirts. Most of the time wearing a tight fitting shirt avoids the problem.

          You could also try an electrode gel. A friend of ours swears by honey under the strap.

          BTW - we also saw this with Polar CS200s as well so it's not by any means restricted to Garmin devices.


          • #6
            We've dubbed it "jersey flapping syndrome" here at Dynastream. The cause is, typically, statically active clothing such as synthetic shirts or cycling jerseys. Usually the problem goes away when your shirt gets damp from sweat or other moisture. However, the problem can be more evident if you wear multiple layers and if the air is more dry. You can make it better in a couple of different ways or use a combination:

            - Wet the electrode area of the strap ONLY. This is more significant with the new cloth strap. Don't run the whole thing under the tap. If you use electrode gel, just a thin smear of the stuff on the electrodes will do.
            - Don't put your running gear in the clothes dryer. It's not good for the fabric anyway.
            - Spray your jersey or shirt with some static guard or rub it with an antistatic sheet for the clothes dryer before you use it.
            - Clean your strap (specifically the electrodes) with a damp cloth after use, and then let the strap air dry. Leaving it inside a damp gym bag is bad for a number of reasons - it isn't good for the electrodes and it may cause the strap to stay 'on' because it's detecting a contact between the two electrodes through some damp clothing or towel.

            If you're having inconsistent HR results then it may be necessary to experiment with the location of the strap on your chest. It's intended for the strap to sit on the ribcage, just below the pectoral muscles or breasts. The lettering on the module should be right-side up so that it reads properly to someone facing you.
            This placement works for most users, but if you go for a reasonable length run or bike and the heart rate data never looks right (i.e. it's jumpy when you're going at a steady effort level, or it's way off compared to your carotid artery pulse rate) then you may have to experiment. Try shifting the strap to the left of center or up and down a little. As Damon suggested, some people have found the strap to work better on the back or even upside down. However, the strap-on-the-back approach may not work well in a bike setup where you have the watch or Edge on the handlebars.


            • #7
              Guys, Thanks for the suggestions. I will try them. Also, I did have this problem with my Polar 625SX as well at times, but it was very spikey versus constant.


              • #8
                Originally posted by T_SMIT View Post
                If you use electrode gel, just a thin smear of the stuff on the electrodes will do.
                A small quantity of electrode gel on the electrodes worked for me. Thanks.



                • #9
                  follow my heart problem with the band. I tested with a 100% cotton shirt and my problem remains. the funny thing is happening in the second half of my career about 8 kilometers. attached a picture to see him for yourself

                  Last edited by alvadom; 09-17-2009, 01:58 PM.


                  • #10
                    That kind of noise is not generally expected when you're that far into a run. Did your strap get very sweaty during the run? Can you post the same graph for the run you reported on 9-13?

                    Does it seem like the strap is slipping out of position during the run? If your strap is the fabric type, unsnap the module from both sides and make sure that the snap contacts are clean.


                    • #11
                      forgiveness but not understand what you mean by 9-13. you repeat it? the normal belt gets wet with sweat and barely moves during the race. indeed, when I take off my shirt back readings to be correct. thus seems a problem of tissue. but as I said that race was the 100% cotton
                      Last edited by alvadom; 09-17-2009, 02:49 PM.


                      • #12
                        Sorry, 9-13 was a reference to the date you posted the first problem (September 13).

                        If a continuous band of sweat develops across the strap (from one electrode to the other) then it can cause the HR readings to become inconsistent, because the sweat is basically causing a short circuit for the strap. So getting noisy data after 4 km of running with a cotton shirt could be a result of this type of problem.

                        With synthetic fabrics, it is more common to have noisy data at the beginning of a run, when the shirt fabric is dry and the HRM electrodes do not have very good contact with the skin. However, synthetic fabrics usually wick sweat well enough to prevent sweat bridging from happening. I wanted to see the graph from your first run to see when the noise occurred in the HR graph.


                        • #13
                          agree. I understand now. is that I am Spanish and do not drive very well English. Here you have the coach of the day 13 with synthetic shirt. as you see the noise also emphasized in the second half of the race


                          • #14
                            Which heart rate strap do you have? The all-plastic one (says HRM1B on the back) or the one that has thin cloth and rubber electrodes (says HRM2-SS on the back of the center module)?

                            If you open the unit to do a battery replacement, look very carefully at the battery contacts to see if there is any evidence of corrosion. If sweat was wicking into the electronics during your run then it could cause this kind of noise.

                            All I can suggest at this point is to keep using it, log your data, and if the symptoms persist then you need to contact Garmin Customer Support, because this is not expected behavior.


                            • #15
                              Link to similar problem

                              I posted with a similar problem before I found this thread. Link below.

                              Basically, high HR data on bike at start of session.
                              Gel didn't solve the problem but I'll try using it more liberally!
                              I'll also try dampening the shirt before I start (I didn't get the problem when I'd just done a swim stage on a Tri!)