No announcement yet.

Heart rate monitor working poorly

  • Time
  • Show
Clear All
new posts

  • Heart rate monitor working poorly

    My wife recently got the 405cx with heart rate monitor and loves the watch. Unfortunately, she hasn't had a good experience with the heart rate monitor.

    I've used the 305 with HRM for some time and haven't had any problems with it, so we tried pairing my HRM with her watch. It works fine when I go for a run with her watch and my HRM, but she her heart rate still doesn't seem to register properly when she uses my HRM either.

    I've uploaded her run from today ( and you can see that the heart rate looks unreasonably high for the first 7-8min (~175bpm) and then it slowly but consistently decreases over a period of about 8min to an impossibly low heart rate of just 40bpm and stays impossibly low (<73bpm) for the rest of her run.

    Does anyone have any suggestions for how she might get it to register her heart rate more accurately?


    Edit: I can upload other runs and non-running workouts which also exhibit this problem. She's never really had any luck getting reasonable data for her HR.
    Last edited by David_U; 09-10-2010, 05:57 PM. Reason: noted that other workouts can be uploaded if it would be helpful

  • #2
    I am not sure about the low end but I notice the same issue on the high end when I do not sprinkle the plastic part of the strap with water first.


    • #3
      She should experiment with wearing the monitor in a few slightly different locations. Generally the best place is such that the center module ends up just below the sternum, with the electrode straps just below the breasts or pectorals (on guys). This can require that she arranges the strap to sit underneath her bra support band. If that doesn't work then sliding the strap toward the left an inch or two may help.

      The strap is handed, so it is intended to be worn with the Garmin logo right side up from the point of view of a person facing the wearer. However, for some people the electrical signal that comes from the heart muscle is polarized differently and they'll actually get better results by wearing the strap upside down. But this is very rare.

      Last thing: You may want to try replacing the strap battery.

      Hope this helps,


      • #4
        With HRM straps I've used in the past (not garmin) I've improved reliability by shaving my chest but I doubt this would work in your wife's case .

        Seriously though I think the first part is possibly OK depending how hard she is running because the HR goes up and plateaus around 180. I think the problem is later in the run. My guess would be that the strap is slipping down and not registering the heart rate properly.


        • #5
          I've seen similar threads on this board where better results were obtained by placing the monitor backwards; yes garmin symbol actually centered on your back. Also some use it on their side; a sensor strip front and back. All are worth a try.


          • #6
            type of shirt I wear affects my HRM readings

            My best wicking running tops seem to create static for the first couple of miles of my runs, making my HR readings way too high. This is especially true on cooler mornings. After the first few miles, the readings are correct. If I wear cotton (yuck) the HR readings are OK.


            • #7
              if your HRM is not working properly than consult with your agency holder or the vendor who selling this type of watch.
              Heart Rate Monitor