? Garmin Heart Rate monitor issues ?

[Z-Knight]

anyone have weird jumps in their heart rate results when using a Garmin monitor? I have the 620 and occasionally I get very weird jumps - like tonight look at my profile:



I know my heart rate did NOT jump from 120 to 170 is a span of 2 seconds and stay at 170. I was a comfortable run and my heart rate was calm. As you can see the hear rate before and after the spike follows the same trend line - so I know it is just a spike because if it was real then it wouldn't come back down to the trend line level like you see above. I've had multiple of these and I know my heart rate is not just flying up like that - it doesn't always happen and I can't figure out the cause. Is it shaking of the monitor, etc? My pace doesn't change, my cadence doesn't change. I've seen people post similar issues but usually attributed to poor contact of HR monitor to chest or something like that.

btw, the drop near the end is correct - that's at 1:10 hr when treadmill stops, and I have to restart it to continue with my 8 miles.

 

[DopeyBadger]

I've definitely had these as well, and typically attributed it to poor contact between the chest strap and my body. My guess is the strap is drying out after a few minutes, which causes the spike, and then you start sweating, it wets the strap and it brings the heart rate back into accuracy. Here's a DCrainmaker post about it.

Here's three I had late in my runs. My only guess at the time was maybe a dying battery (these all occurred in a span of two weeks) because it occurred so late in the run and because like you there was no cadence or pace explanation.

 

[Z-Knight]

thx - I forgot about DCrainmaker, that's a great review site.

btw, since you posted and noticing your hear rate is steady from the start. Any thoughts on why mine ramps up before it evens out - do you think I'm not giving it extra effort early on? It is probably a result of running on treadmill at constant pace so I don't need to give it effort initially until I start getting tired.

 

[DopeyBadger]

thx - I forgot about DCrainmaker, that's a great review site.

btw, since you posted and noticing your hear rate is steady from the start. Any thoughts on why mine ramps up before it evens out - do you think I'm not giving it extra effort early on? It is probably a result of running on treadmill at constant pace so I don't need to give it effort initially until I start getting tired.

What kind of warm-up/stretching routine do you follow prior to starting your run? I do a 10-15 minute dynamic stretching routine which raises my heart rate just a tad. Then I walk for 3-5 minutes to where I like to start and my heart rate drops again. So, it's possible I've already had this heart rate acclimation during the warm-up and could explain why it doesn't show on mine but does on yours.

I do know there is an effect of warming up (moreso, raising HR before the run or do very slow running prior to starting the real workout) on the energy system (aerobic vs anaerobic) use and that it requires a minimum of ~6 minutes for the aerobic system to be primed and ready to use. Potentially, although I'm not positive, this may also effect how the heart rate is stimulated at the beginning of exercise.

 

[BuckeyeBama]

I have read that the Garmin HRMs are sensitive enough to register static electricity as heart beats. The theory is that while your shirt and body are still fairly dry because you have not really started sweating yet, your shirt rubs against the HRM with every step. If it is a tech shirt and it is dry, the steps/rubs can confuse the HRM and produce a heart rate reading like that. Mine has done similar things, usually on drier and/or cooler mornings.

To stop it I now do a few things, and they have stopped this every time for me. First, I dampen my shirt just over the HRM snap-in device when getting dressed on a low humidity morning. Second, I pay attention to my heart rate for the first few minutes of my run. If it jumps up, I hold my shirt to the HRM with one hand, essentially placing my hand over my shirt in the middle of my chest and holding to to my chest. This stops the shirt/HRM friction and brings the reading back down to my real heart rate. I sometimes have to hold this for a few minutes of running for it to stay down.

Your shirt does not have to be holding static electricity for this to happen. Just the rubbing of the dry tech fabric against the plastic HRM device is enough on drier mornings to create the static at low levels - or so goes the theory. But the stuff that I do above stops it for me. YMMV.

 

[Z-Knight]

What kind of warm-up/stretching routine do you follow prior to starting your run? I do a 10-15 minute dynamic stretching routine which raises my heart rate just a tad. Then I walk for 3-5 minutes to where I like to start and my heart rate drops again. So, it's possible I've already had this heart rate acclimation during the warm-up and could explain why it doesn't show on mine but does on yours.

I do know there is an effect of warming up (moreso, raising HR before the run or do very slow running prior to starting the real workout) on the energy system (aerobic vs anaerobic) use and that it requires a minimum of ~6 minutes for the aerobic system to be primed and ready to use. Potentially, although I'm not positive, this may also effect how the heart rate is stimulated at the beginning of exercise.

I do a 10 minute warmup walk, followed by 3 minutes of stretching. I then start at slow rate for 3 minutes before I begin the run. I always see this slow ramp up of my heart rate but i usually dont feel like i could push it early on - it takes about 3 to 4 miles before I feel relaxed and know i could pick up the speed...so my heart rate is kind of confusing to me. But I'm still slow and trying to get back in shape after my stress fracture. 500 miles after 11 weeks, but still only 80%. Need to freaking lose weight!!!

 

[Z-Knight]

I have read that the Garmin HRMs are sensitive enough to register static electricity as heart beats. The theory is that while your shirt and body are still fairly dry because you have not really started sweating yet, your shirt rubs against the HRM with every step. If it is a tech shirt and it is dry, the steps/rubs can confuse the HRM and produce a heart rate reading like that. Mine has done similar things, usually on drier and/or cooler mornings.

To stop it I now do a few things, and they have stopped this every time for me. First, I dampen my shirt just over the HRM snap-in device when getting dressed on a low humidity morning. Second, I pay attention to my heart rate for the first few minutes of my run. If it jumps up, I hold my shirt to the HRM with one hand, essentially placing my hand over my shirt in the middle of my chest and holding to to my chest. This stops the shirt/HRM friction and brings the reading back down to my real heart rate. I sometimes have to hold this for a few minutes of running for it to stay down.

Your shirt does not have to be holding static electricity for this to happen. Just the rubbing of the dry tech fabric against the plastic HRM device is enough on drier mornings to create the static at low levels - or so goes the theory. But the stuff that I do above stops it for me. YMMV.

That's good info, thx. For me though it may not be the cause because i had it happen later in runs and usually by 15 -30 minutes I'm pretty soaked...like puddles form behind me, soaked

 

[opusone]

It looks like it could be picking up cadence instead of HR during the spike. I know with the optical sensors, they sometimes register cadence if they aren't picking up the heart rate which makes sense on a loose fitting wrist watch based on how optical sensors work; however, I can't figure out why Garmin's HRM-Run strap would possibly default to cadence since it doesn't use an optical HR sensor. So, my post is likely worthless to you.

 

[BuckeyeBama]

It looks like it could be picking up cadence instead of HR during the spike. I know with the optical sensors, they sometimes register cadence if they aren't picking up the heart rate which makes sense on a loose fitting wrist watch based on how optical sensor's work; however, I can't figure out why Garmin's HRM-Run strap would possibly default to cadence since it doesn't use an optical HR sensor. So, my post is likely worthless to you.

I agree that it is, somehow, likely picking up the cadence. Probably tied to static electricity in some way, but being soaked with sweat would seem to eliminate that. I have never had it happen to me once I got a full sweat on.

Is this one of the newer straps that measures cadence? Maybe it is messed up and reporting metrics incorrectly. I have those new straps and have never had this problem, but it may be a possibility.

 

[Z-Knight]

It looks like it could be picking up cadence instead of HR during the spike. I know with the optical sensors, they sometimes register cadence if they aren't picking up the heart rate which makes sense on a loose fitting wrist watch based on how optical sensors work; however, I can't figure out why Garmin's HRM-Run strap would possibly default to cadence since it doesn't use an optical HR sensor. So, my post is likely worthless to you.

You know what, looking at other cases where this happened and where it happened for more of the run, it does actually look close to the cadence counts - that's so weird. I doesn't match the exact cadence number that the cadence is reporting at the same time, but it is close. Usually on my slow runs i havena cadence of 167-169 and i see that highest kind of heart level. On another faster run my cadence wad 173-175 and the heart rate spiked to those numbers. Hmm. Interesting. Although the plot above doesn't exactly reach my cadence for that run. Who knows. Hopefully my heart rate is fine - though it doesn't feel weird or high during those times


Edit: i have the garmin 620 hrm+run chest strap so it.does have cadence, heart rate and ground contact time, and vertical oscillation - i'm freaking bouncy

 

[opusone]

You know what, looking at other cases where this happened and where it happened for more of the run, it does actually look close to the cadence counts - that's so weird. I doesn't match the exact cadence number that the cadence is reporting at the same time, but it is close. Usually on my slow runs i havena cadence of 167-169 and i see that highest kind of heart level. On another faster run my cadence wad 173-175 and the heart rate spiked to those numbers. Hmm. Interesting. Although the plot above doesn't exactly reach my cadence for that run. Who knows. Hopefully my heart rate is fine - though it doesn't feel weird or high during those times

Edit: i have the garmin 620 hrm+run chest strap so it.does have cadence, heart rate and ground contact time, and vertical oscillation - i'm freaking bouncy

With the 620 and HRM-Run monitor, you actually have two cadence sensors: one in the watch, and one in the HRM-Run strap, so that could possibly be the reason for the cadence difference you mention.