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Heart rate monitor stops working during exercise

I am a 40 year old male, about 25 lbs overweight, and I try to exercise at least three times per week on a treadmill. I am usually on the treadmill for 30 to 45 minutes, and try to keep my heart rate below 170. It is typically at least 150 after 8 minutes or so on the treadmill. I have had PACs almost constantly for over a year. I am on Flecainide (100 mg twice per day plus 50 mg at noon when I remember to take it) and propranalol at my discretion (stagefright). My GP and cardiologist of course say, no problem, it's just superficial. I can deal with that, no big deal; it's just hard to get used to the anxiety and fish-flopping-in-the-chest feeling all the time. I have an issue during exercise though - sometimes when I am exerting fairly well (steep uphill fast walk or more flat jog/run) and my pulse is at least 155, I feel a sharp pinch or shock in the center of my chest and my wireless heart rate monitor suddenly reads zero (no signal), after which I stop running and try to relax, and the monitor begins working again when my pulse is down around the 110 - 115 range. This usually happens maybe once a week, but recently has been happening more frequently. Today I exercised for 45 minutes (but have really slacked off for the last two weeks, only exercising once per week for the last 14 days, yes I feel guilty) and this happened 4 times. About a month ago I asked my cardiologist about the sensation and subsequent HRM issue, and he had no idea what was happening. He thought maybe my chest strap was shocking me. I doubt that, it feels like what another person described on this forum, and I believe that was generally thought to be a PVC or PAC. I can't find anything about a heart rate monitor suddenly losing signal. My instinct tells me that it's seeing the erratic electric charges and becomes confused, but I don't know if there's any substance to that. It is unique enough that when I feel the pinch, I know the HRM is going to stop working in the next 5 seconds. This cause and effect is evident. Any ideas? Might this be something more than a PAC? Thanks in advance for the help.
5 Responses
612551 tn?1450022175
The Pulsar and other HRM I have used all use the same 3 volt dc (battery) for electrical power.  There is no reason I can think of for the electronics to use this dc power to generate any high voltages, enough to shock you.  And even if it did, the energy taken out of the battery would run it dead in a few shocks.  How is the battery hold up?

I have also experienced strange reading, and a loss of reading would suggest to me the chest pick-up has just lost the signal due to slippage or loose contact.

You mention 25 pounds over weight, but don't mention you height.  But, even if you under 6' I doubt that the extra 25 pounds could interfere with the HRM chest strap contact... but check that out too.
1147530 tn?1314821596
I can't explain the shock you feel, but just to let you know, my HRM (Polar) goes to 0 for a few seconds while I'm on the elliptical and holding on to its handles which are also heart rate monitors.  I know my pulse did not go to 0, although that's what the Pulsar is saying, because the elliptical is still picking up a pulse.  Or the opposite happens, the elliptical monitor goes to zero but I hear my Polar ticking.  So there must be some transmission wave interferences.
Then when I have a lot of palps, I wear the Polar around the house, and every time I walk through some hot spots (close to the TV, etc.), it goes to zero then resumes.  If I bend down, it sounds as if I'm having multiple pvc's in a row, but I'm not since I can feel the normal rate in my neck pulse.  I tested it every which way to make sure it's not giving me funky readings and me thinking it's my heart doing those things.  
Maybe the PVC's following your shock sensation are adrenaline driven since you are now on alert and anticipating something.  It would be interesting to see the results on a different monitor.  Let's know if you find some answers.
612551 tn?1450022175
Right "Polar" is the brand name name I meant to give.  Pulsar is a popular wrist watch brand and it sounds right.

I have another brand of HRM too, forget the brand, and it does the same thing - drops out at times.
Avatar universal
My experience with a Polar heart monitor is that it will jump around quite a bit during bouts of PVC's  ----up and down 20 or more.  The device averages heartbeats over a time period and just reports what has been detected during that time.  I also observed it will go to zero when HR is really chaotic and it can't seem to sink into rate.
Avatar universal
I am a 49 YO white male cyclist. My HRM will consistently go to 0 when my HR is 175+ for more than a few minutes.  This happens regardless of location.  I have used a Polar S150, Blackburn Delphi 5.0, and Garmin 705 and they ALL do the same thing.  My DR said it is not a cardiac problem, my EKG is normal, but am scheduled for a stress test (just to check).  I did all the equipment checks (band snug and moist, eliminated all possible electronic interference, and changed all batteries) to no avail.  I have contacted the individual HRM makers and nobody has any ideas.  If anyone finds even a possible solution I am all ears.

Jon - ***@****
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