Training & Nutrition - HRM has 30 bpm fluctuations?

I just bought my first HRM, the Sigma Sport Coach Heart Rate Monitor, and I tried it out while running yesterday (I haven't tried it on my bike yet). It read my resting pulse consistently, but I noticed while I was running that would jump back & forth between 128 and 158 bpm while I was running at an even pace along a level stretch. Is this normal or is the HRM to blame?

Your heart rate will not change that much from my experience. I have had problems with a treadmill giving me a false reading while wearing the monitor, as it actually doubled the heart rate for about 30 seconds. I was using my watch at the same time, that is how I know it was showing double. Never had the problem again.

Definitely not normal, I would contact where you purchased it from and check on an exchange.

HRM can be expected to do this. If they are monitering the electrical activity
of the heart, they can not be expected to disregard the electrical activitiy of
other muscles in the vicinity of the sensors, so when running you are hyper
ventilating and the chest/pectoral and shoulder muscles are all very active
contributing electrical inputs sometimes counted as a heart beat. In addition
the skin contact of the sensor can intemittently loosen and tighten under
running stress as your chest changes shape while breathing and pumping the
arms. Result is missed beats and missed counts. Changing the HRM will not
change these reasons for variable counts. Even hospital grade moniters will
vary 5% or more on someone laying quietly in bed and can bounce the trace
from the bottom of the screen to the top in response to arm or chest motion
such as adjusting the blanket, or reaching for a drink.

That may well be true, but... In the past (before my battery died for the millionth time) when I would download my Polar HR data to a scatter-o-gram, it was extremely rare for me to see any outlying data points. I'd also occasionally look at beat-by-beat tables, and only rarely saw the types of outliers you describe. It may more likely be electrical interference (overhead lines, other people with monitors, etc.).

Do you exercise with others who may be using HRM's? Do you exercise in the area of high tension lines? That, or a defective monitor, is more likely the cause of your problem.:)

Do you exercise with others who may be using HRM's? Do you exercise in the area of high tension lines? That, or a defective monitor, is more likely the cause of your problem.:)

Thanks for input so far. I was running solo nowhere near any power lines.

flapping nylon clothing can also cause weird readings. my garmin 305 frequently reads around 230bpm when I'm descending wearing a particular (flappy) jacket.

try turning on an off if it happens again or make sure good contact with your skin.

if it is not coded you can get someone elses readings at times
powerlines and in TX the electric farm fences mess me up

it should not jump around at all, just have some delays on intervals.

Nylon and some polyester garments generate spurious readings. Try wearing different tops. Lick the HR transmitter's contact patches thoroughly before putting it on. Try smearing some saliva on them if you are getting spurious readings and not sweating. Sweat usually takes care of it. Needs to be an electrolyte. Tap water doesn't work. Duh-Dum cream is available to assist in getting good contact, but is usually unnecessary.

Try smearing some saliva on them if you are getting spurious readings and not sweating. Sweat usually takes care of it. Needs to be an electrolyte. Tap water doesn't work.
Thanks - I'll try this!

Put some of that HRM gel on the contacts. Maybe if there's not good enough contact (no moisture, strap too loose) it can give false numbers like that.

I don't usually have any problem because it kind of just get squeezed under my man breasts. There's usually plenty of moisture down there.

no. it should be accurate. the fix is listed above but


make sure the strap is tight

spit on finger, rub spit on the contacts of the strap
----
overhead high voltage wires, or transformers can cause it to go wacky, so
make sure this isn't happening under wires or near transformers within 30 feet

I have similar problems, especially when the humdity is low and/or a breeze is there to dry up moisture. It never happens in heat, humidity, and after I really warm up sweating. As someone else said, nylon and synthetic material makes it worse. Also some materials generate statisc electricity. Garmin says to dampen your jershey before going out. Also somone else mentioned use of geals or saliva on the chest pads. I usually do that verey time.

I would compare it to how it does on the bike, where there isn't the bounce factor. I'll bet there's your answer.

but I noticed while I was running that would jump back & forth between 128 and 158Maybe a loose chest strap? But if the numbers are not "sticking" -and then jumping 30 bpm - there's something else wrong.

All the HRMs I know of would be displaying plenty of numbers in between 128 and 158 - not just jumping 30 beats. So if you see stuff like 128 138 146 140 150 156 150 140 136 - you may have some other wacky stuff going on with your heart.........

It sounds like your losing contact. They sell lubricating gel at the store, just put a little on and that should do it.

Tap water doesn't work. Duh-Dum cream is available to assist in getting good contact, but is usually unnecessary.

why wouldn't tap water work? in HS a chem experiment we did was involving the electrical conductivity of tap water. by trying using the tap water as a conductor between two electrodes on a light bulb comparing it to distilled water and the tap water worked.

why wouldn't tap water work? in HS a chem experiment we did was involving the electrical conductivity of tap water. by trying using the tap water as a conductor between two electrodes on a light bulb comparing it to distilled water and the tap water worked.

I don't think it's as much a problem of conductivity, it's more a problem of having continuous contact. The water would make a very thin layer, but maybe the lotion can provide a thicker layer between the the chest (or back) and the strap. Anyways, maybe I'm way off, but I think it's another factor to keep in mind.

^^ that makes sense
didnt think about water drying off haha