Garmin 910XT – Heart Rates Spikes, Dropouts & Straps & Stuff

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Heart rate and power
Heart rate and power (Photo credit: samwebster)

Winter arrives and my August-purchased 910XT suddenly develops heart rate spikes. Sigh!

Some of you will be having Garmin heart rate recording issues from new. Others, like me, think (or thought) they have got a good unit…for a while at least.

Here’s a summary of some heart rate ‘facts’ by on my non-statistically sound research!:

  1. All major brands seem to suffer heart rate recording issues
  2. ANT+ heart rate will never transmit through water
  3. Heart rate spikes are usually a problem with the strap…not the sender unit and not the receiver (watch)
  4. It can be hard to edit heart rate base data with Garmin software (but it can be with SportTracks)
  5. Heart rate spikes may be caused by static
  6. Static is created only when there are two different materials…your body hair might count as one material
  7. Heart rate spikes may be caused by incorrect contact between the strap and body.
  8. A commonly held view is that licking the sensors on the strap first help with contact.
  9. Garmin are pretty good about sending a replacement strap (not sender unit) whilst under warranty.
  10. Newer/soft straps seem more prone to heart rate error than the older hard straps.
  11. Heart rate spikes tend, for me, never to happen after 20 minutes of use
  12. Dropped heart rate reading are either simply a temporary lost contact with the strap and body or something far more sinister and faulty elsewhere. Possibly could be interference with another unit I guess.
  13. Garmin transmitters fit the competing Polar straps and work on them.
  14. Garmin recommend a medical contact gel to ensure a good signal is picked u from the body/strap contact.


  1. Lick and tighten
  2. Go back to an old Garmin hard strap
  3. Get a new, warranty replacement soft strap from Garmin
  4. <Buy> a replacement on Amazon – a full replacement is often cheaper than just the strap
  5. Wear a tri-suit and shave body hair
  6. Use medical gel if licking doesn’t work
  7. Turn on and wear the watch and strap for 20 minutes prior to starting exercise
  8. Buy <THIS> Polar soft strap and put your Garmin transmitter onto it
  9. It only happens in your warm up so don’t worry about it
  10. Edit the data afterwards with SportTracks

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Shaun McDonough

Most of the problems I’ve had with the new straps are from static. The charge comes most likely comes from the dryer where your clothes are rubbing(friction and different materials especially tech/polyester) together as it dries. The problem is magnified in dry environments – i.e. winters and places like Colorado. In more humid environment the electrostatic charge dissipates in the first part of your workout. Electronics do not like electrostatic charge and it will destroy the device just give it some time. In the winter I spray my tech shirts(polyester) with Static Guard(available at most grocery stores). I’ve found that this virtually illuminates the dreaded spikes at the beginning of the workout(which can be the whole workout in the winter).

Shaun McDonough

Bottom line, if I don’t spray my tech shirt with Static Guard or water in the winter months, the first 30 min of a run will be false heart rate readings. I sweat like a pig all times of the year. It just takes that long to dissipate the static from my tech shirt. I believe this static causes premature heart rate monitor failure.

Shaun McDonough

I forgot to mention that I do wet the hrm strap.


Heart-rate monitors units are flraiy simple things. They strap around your chest to hold a couple of electrodes in contact with your skin to detect the beating of your heart, transmitting this information wirelessly to a nearby receiver. The Garmin offering is no different in it’s function. But it is different in a couple of other ways. The piece with all the brains in is longer than some other brands, making up half of the band that the complete unit forms around your chest. It’s made from a pre-shaped soft plastic, with ribbed electrode pads built in. I’ve found this shape to be very comfortable, fitting neatly round my chest and staying in place with no bother. In fact it’s so comfortable that I really don’t notice I’m wearing it, even after 14 solid hours of cycling. I use it with a Garmin Edge and have never had any problems with signal, it usually syncs with the main unity within 10 seconds. When riding in a bunch with some other users, it doesn’t suffer from cross-talk staying paired with my own Edge and keeping my heart rate to myself. The battery life is very good, I found that it needed… Read more »