Garmin v miCoach

April 13, 2011

The HR spikes caused a research project and this goes on until I know my heart is not to blame for the scary spikes while I run.

During the Sunny Bay hikerun my friend used my Garmin HRM below shows no spikes, he wore the belt high up in the chest and used gal to wet the contacts.



I used miCoach and there were no spikes. I did walk-run intervals (0.5k walk, 0.5k run) at the 2nd half of the run. It’s apparent that my heart needs 3~4 minutes to slow down and ramp up. I could have the entire run within yellow zone if I didn’t do intervals. The conclusion is that if HR spikes are of short duration, say 1~2 minutes, those must be signal spikes.


In the Garmin’s manual

If the heart rate data is erratic … you may have to tighten the strap on the chest or warm up for 5-10 minutes.

Heart Rate Monitor Tips

  1. Make sure the HRM is snug against your body
  2. Reapply water, saliva, or electrode gel to the electrodes. Clean the electrodes, dirt and sweat residue can interfere with HR signals
  3. Wear a cotton shirt or wet your shirt if suitable for your activity. Sythetic fabrics that rub or flap against the HRM can create static electricity that interferes with HR signals
  4. Move away from sources of strong EM fields and some 2.5 GHz wireless sensors … sources of interference may include very high voltage power lines, electric motors, microwave ovens, 2.4 GHz cordless phones, and wireless LAN access points.

Putting their HRM together I can see (not that obvious from photo below) that miCoach’s strap has the plastic continuously built into the fabric from the left to the right electrodes (contacts). The Garmin HRM electrodes are two plastic contacts on both sides of your chest.

Nothing is better than side by side comparison so today I put both miCoach and Garmin HRM on during my morning run.

The miCoach chart looks fairly typical with HR max at 165, I walked home after 5k and left the miCoach on.


The Garmin HR pattern looks the same with HR max at 164.


I wore the Garmin HRM high up in the chest and adjusted the length of both to be the same such that their tightness is the same on my cylindrical chest.

So what’s my conclusion? I think the Garmin HRM could be too slag and it wasn’t a snug fit after 4 months use. I’m pretty sure I wear it correctly although Garmin manual doesn’t tell me how, the miCoach manual has a figure showing where the HRM should be worn.

I know by now the HRM works either way, e.g.

from this site.


from this site.

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