Heart Rate jumps

[CarbonEndurance66]

Has anyone had heart rate fluxuations? I.E. kowing that you are in you 60% HR zone but having your iBike show something closer to 90% Max HR? I have had this issue with my Polar and can't figure out what is going on. I'm am 23 in great shape; my HR Max is around 200 I think and I try to stay below my 75% max heart rate mark but seem to get these crazy spikes in my BMP. I can send out a ride profile if more detail is needed.

[racerfern]

The most common reason for HR irregularities is static electricity. The strap can be confused by your jersey fluttering in the wind against your chest. If you haven't produced enough sweat to make a good contact, that can be an issue also. I've taken to using a conductive gel. http://www.uni-patch.com is the one I buy at a local store. I happen to wear a UA compression jersey as a base, so that tends to hold the strap snuggly and that helps too.

These are not problems unique to the iBike HR strap, my Garmin strap can also have this problem.

Also be sure to wear your strap with the logo right side up. There can be a polarity issue and excessively low readings or no reading at all if the strap is worn upside down.

[leonsrocketcar]

Same as Fernado, I saw same type of issues with loose jersey's (and this was both my polar and iBike straps). I wear specialized base layer snug against me and no issues.

[Site_Admin]

Polar tried to fix this with their coded strap, but to no avail.

There's some interesting information on just how un-aero zippers are at speed in the slowtwitch forum. I'm not Cobb's biggest fan, but I think he has a point that we emphasize with the iBike... Be Aero. Be skinny, be low, keep your head down, keep your knees in, lose weight, and remember that air is a gas that can act like a fluid.

[MultiRider]

You might also want to see if the spikes occur in the same geographic location. Both my iBike and Garmin 305 report HR in the 225-250 range at the same place. Actually, they both do it at a particular place on my normal close-to-home route and they both do it at a particular place in Deer Creek Canyon. Probably some type of electromagnetic interference from a man-made source.

Though such spikes probably don't affect averages enough to worry about, Richard walked me through the process of using Excel to edit the iBike file, find the offensive spiked values, and change them to an average of the before-the-spike and after-the-spike numbers. This can be done both for spurious HR spikes as well as spurious wattage spikes. The primary value to me was that when I got rid of the 2000 watt values, the scale on the 'y' axis on the graph changed to something much more readable. It was very compact when scaling to include the spurious 2000 watt spike; it was much easier to read when it only had to go up to 600-700 watts.

[william.b.thomson]

I likewise have had problems with hr rate fluctuations. First of all, there is a location early in every ride I take that seems to have a problem. Second, the problem appears to diminish shortly after I have settled into the ride, which implies that my skin is not creating a good contact, not sweaty enough, early on. I have tried dousing myself with water, but that does not help. I am going to try the gel, but more importantly, I have learned that the few spikes, early in the ride, only marginally (very marginally) influence the total average numbers. I will admit, however, that it annoys me to no end.

[Robert]

I had similar problems with my HR strap not making good contact till I had started to sweat a bit. Never tried the gel, but if you use chamois cream or butt butter or something similar, it works. I just put a little on my strap before I put it on and that has solved my issues.

[gregh3285]

I've had this issue as well. The first time I saw it, I really worried. My HR hit 190-something in the first mile of my ride. Was my heart going to leap out of my chest cavity? The second time, I thought it was electromagnetic interference. The third time it happened, I thought it was a low battery (and changed it). Finally, I realized (and have experimented enough to feel comfortable with my hypothesis) that it was the heart rate strap not being wet enough. Before I ride, I put a little water from my water bottle on my hand and then dampen my heart rate strap and my skin underneath. If I do that, I do not see my heart rate hit 240 in the first couple miles of my ride (like I have seen in the past). So, a) clear the wind offset, b) check tilt cal, c) dampen HR strap, and d) reset initial altitude. Rituals to follow...

[iodaniell]

May sound "gross", but I lick my heart rate chest strap's contacts every time before putting it on. Seems to work.

[scittkit]

I had recently changed a battery and when I replaced the cap the o-ring did not seat right and stuck out beyond the cap. I did not notice and went for a ride. My heart rate would go from 140 to 230 for no reason. When I replaced the o-ring the problem stopped. I think either sweat or static electricity breaching the case caused the erratic reading.

[racerfern]

Static electricity is the enemy in this case. You can easily see HR jumps on downhill fliers especially into the wind. As I noted earlier, wear an under garment or you can also try turning the strap around and wearing it on your back. For sure you will need to moisten it with a gel for back usage since sweat takes a lot longer to build up.

[schroed15]

HR spikes (180+ while coasting) on fast descents seem to be created by my jersey fluttering in the wind. When it spikes, I can bring it back down by pulling my jersey away from my chest (just verifies the source of the problem).

Anyway, a tight base layer didn't stop the spikes for me, but I have had success by taping a strip of foam rubber to the outside of the HR strap to help absorb the contact from the jersey flapping. It's kind of a pain in the rear and adds yet one more step to the pre-ride process, but it does seem to take care of most of the HR spikes.

FWIW, I used to have the same problem with the older model plastic Polar straps. I have not experienced the same issue with the Polar WearLink strap, though, which has a fabric (some sort of nylon?) contact area rather than plastic. Just wonder if the fabric helps dampen the "jersey flapping"...

[scittkit]

Maybe wearing it backwards or buying tighter cloths would be a better solution.