My beating heart: Chest monitor vs Garmin wrist sensor...

[ktsok]

Today was the day to test out the CooSpo Heart Rate Monitor on a chest strap. I have been suspicious of the accuracy of the Garmin wrist sensor whilst running since my failed attempt to do a ‘heart rate zone’ run. My heart appears to beat too furiously to even achieve a brisk walking pace in Zone 1, let alone jog in Zone 2. I basically ended up walking 10k with the odd sort of doggy trot here and there and still averaged 136bpm.

I then tried a run where I could only breathe through my nose, in an attempt to keep the effort, pace - and heart rate - low. This quite pleasant run resulted in a 170bpm average. Back to the drawing board.

Then I noticed that my cadence and my heart rate were remarkably - and suspiciously - similar. On the nose-breathing run my average HR was 170bpm, my average cadence was 175spm. On the 10k walk/trot my HR was 136, cadence 139. And so on, back through the last few months. The biggest difference in average heart rate and average cadence was 6 beats/steps, and usually, there was a difference of only 2 or 3 beats/steps. There was a similar pattern in maximum heart rate and cadence figures.

So I unpacked the CooSpo, wet the sensors and strapped it round my torso. It beeped to let me know it had found my heart, then when I selected the Run activity on the Garmin it connected to the CooSpo. Seamless. And off we went, gadget girl and her gadgets. The phrase ‘all the gear and no idea’ was drifting around somewhere, but hey, whatever gets us off the couch, right?!

I had ‘Fantastic Mr Fox’ on Audible to listen to and so the 5k passed with Boggis, Bunce and Bean and their shotguns and mechanical shovels. It felt tougher than my last run and I couldn’t maintain nose breathing the whole time, but plodded on nonetheless.

Then it was time for the big reveal. In terms of effort, I felt I worked harder today than during my previous run. So it was interesting to see an average of 10bpm less, at 160bpm, lower than I have seen for a long long time. My cadence? 175spm, a difference of 15 beats/steps. That’s pretty significant given the previous stats and indicates that the Garmin wrist sensor is indeed locking into my cadence, rather than my heart rate. Which doesn’t matter a bit unless you want to try training in heart rate zones, when it might mean the difference between a slow walk and a jog.

None of this changes the fact that my aerobic fitness could do with a lot of improvement! But perhaps my heart isn’t about to explode on a slow run.

Perhaps one day I’ll dump all the tech and just enjoy running... but not just yet 😉

Have a good week, peeps!

[Dexy5 Graduate10]

It is intriguing isn’t it? Today I wanted to run at around 130 bpm zone 3 on garmin but spent most of my time in zone 4 even though I was fairly slow. I did do a few slopes for a change but it didn’t return to 130s. At least that’s better than parkrun where I am in zone 5 most of the run. My resting HR is average 54, so is high compared to UTS.

Enjoy your experimentation. 🧐

[ktsok in reply to Dexy5]

Strongfuse said that his wrist sensor was more accurate when he wore it further up his wrist and tightened the strap... do you see the same correlation between cadence and heart rate in your stats? Or maybe we are just hummingbirds!

Funny enough, I had a body scan thing done last year and my metabolic age came out at 27 (I was 42). I guess even though I’m not aerobically fit I’m pretty muscle-packed from climbing for 20 years. So maybe metabolic age as opposed to biological age is a better calculation for maximum heart rate?

[Dexy5 Graduate10 in reply to ktsok]

My max and average cadence is 37 more than my HR so no cadence locking on my garmin.

[sTrongFuse Graduate10 in reply to ktsok]

I pretty much ignore the heart rate data from my Garmin, and when I do look at it, I look at the trend rather than the numbers.

When I started, it would tell me that about 90%+ was in the maximum zone, which was clearly wrong. The trick of wearing it a bit higher up my arm helps, but I still spend more time than is probably likely in the top zone and almost everything else is the next zine down.

I've kind of got to the point where, so long as everything seems to be working, and my heart isn't actually exploding out of my chest and spontaneously combating in front of my eyes, then I'm probably OK.

The only stats I'm really interested in are how far I've run, how long it took me and whether or not I'm still vertical at the end. So far, so good...

[Kallyfudge]

My wrist sensor is pretty useless when running, I dont get cadence lock but my HR will be either OK or 40-50 bpm lower than it is. Have been using chest strap for a while, I wouldn't tell anyone to rely on wrist based for running, I use mine just to track resting heart rate.

One other thing to consider, now you know your HR accurately, you probably don't know your Maximum HR, unless you have had it tested. Definitely don't rely on a formula , for e.g. the classic MaxHR=220-age, max HR is variable amongst individuals, it doesn't tell you how fit you are, 2 olympians of same age can have 195 and 145 for example. But relying on an age based calculation is like basing your height on your age.

Its only important for working out your zones.

[ktsok in reply to Kallyfudge]

Nope, don’t know my max HR. I don’t think I’m fit enough to sustain the level of effort to calculate it, to be perfectly honest! And I read somewhere your max HR can change day to day so even the lab tests results aren’t set in stone... But I do know my metabolic age (as opposed to biological age), which is 15 years younger. And if I apply that to all the formulas, it makes more sense!

[E27M14 Graduate10]

Interesting...... i’ve Just looked back through my recent runs and I can’t be absolutely sure because my memory can be a bit rubbish, but it looks like my average heart rate is the same as my average cadence when I am running on my own, but they are quite different, with my heart rate being significantly lower, when running with dog..... which is on a lead held in my left hand, where my watch is!!

[ktsok in reply to E27M14]

That’s odd! I guess it can’t be explained by your dog pulling you and therefore you are using less energy?!

[E27M14 Graduate10 in reply to ktsok]

Maybe her company calms me...... apart from when we see cats or squirrels and she tries to pull my arm off!! But generally I think maybe it’s because I keep my arm quite still to avoid pulling her around, and therefore my watch is actually reading my heart rate rather than picking up the cadence of my arm swinging!

[ktsok in reply to E27M14]

I now have an image of you trying to run along with your arm sticking out - without the dog 😜

[Irish-John Graduate10]

I love "real world, real people" experiments

Thank you for this

Wishing you many happy (and no chest bursting!) miles in your future

[ktsok in reply to Irish-John]

Cheers IJ!

[UnfitNoMore Graduate10]

Interesting research. I’ve often wondered how accurate cadence is too 🤣. I may invest in a chest strap... and a foot pod.

[ktsok in reply to UnfitNoMore]

Gawd. We will be looking like cyborgs on our runs soon! 🤖

[UnfitNoMore Graduate10 in reply to ktsok]

🤣

[MarkyD Graduate10]

That's a proper scientific study there, ktsok. I like seeing gadgets being held accountable for their slightly suspicious foibles. Great work.

Cadence lock is a well-known artifact of wrist-worn heart-rate sensors and they really do need a good connection to the skin. Funnily enough they work better on a slightly chubby wrist (like mine!) where they can sink into the skin, keep light out and see a vein. More skinny folks can struggle to get the watch tight enough for accurate HRM. Garmin recommend wearing the watch a little loose during the day, and tightening up for activity tracking. I once saw a fantastic HRM plot from a mate at parkrun. HRM was all going to plan, and then he ran into fog. There was a rapid cooling of his skin temperature and the HRM dropped about 30 bpm. It kind of calibrated itself out during then next 5 minutes.

[ktsok]

Cheers MarkyD. It’s great to have this benevolent forum where I can indulge my inner running geek!

The Garmin watches are pretty huge and wrists don’t tend to carry as much weight as other areas. I have been wearing it pretty tight but it doesn’t seem to have made a difference. It’ll be interesting to see if the chest monitor continues to read lower over time.

PS. I feel like cold fog might be my friend; I’ll be out in it next time it descends!

[cheekychipmunks Graduate10]

I think you’re right about the Garmin HR monitor picking up the cadence occasionally ktsok. My HR is naturally very very low, at rest and whilst running, but when I did my 19k about a month ago it was pouring with rain and my wrist was obviously soaking wet.

My stats showed my HR at an average of 164 - unheard for me - there’s no way I could have run if that was correct. I’d have keeled over for sure! I’ve just gone back to check that run, and sure enough my average cadence was 163 that day! I hadn’t noticed the correlation before. 🏃‍♀️🏃‍♀️🏃‍♀️

[ktsok in reply to cheekychipmunks]

Oooh that’s interesting. Thankfully it doesn’t do that all the time for you. Maybe moisture/sweatiness is a factor?! I sweat rivers within minutes...

[cheekychipmunks Graduate10 in reply to ktsok]

Ahh, and I’m not a very sweaty runner at all. I think we have discovered the possible issue! 😅

[SlowLoris]

If you connected the CooSpoo to your phone and not to the watch then you would have two records that you can compare. That would tell you if the Garmin was off track. Having an average cadence close to an average heart rate (or further from it) doesn't really give a definitive answer.

If you look at Garmin Connect on a computer you can run the cursor along cadence and heart rate for simultaneous figures. There might be times when they coincide but one locking on to the other should be fairly obvious. Generally for many people they are often going to be in the same neck of the woods.

[ktsok in reply to SlowLoris]

Yes, there aren’t any definitive answers yet! Both good suggestions, thank you 🙏

[seaspaniel in reply to SlowLoris]

Excellent suggestion. Proper Science.

[Setters Graduate10]

Well you have reassured me, last couple of runs I have noticed some very high spikes on my HB, whilst for the rest of the time it’s been relatively smooth, I was sort of worried about this, but as I feel perfectly fine, put it to the back of my mind as something to watch. Now after reading this I put the Garmin HB and pace overlay together, and guess what they are correlating exactly, Phew so looks like my heart is not giving up just yet. Will look at chest monitors as I am always running in top two zones.

[seaspaniel]

I wasn't aware of the cadence lock but I can see how it would work now.

I'm slim wristed but I get an acceptably accurate read from the wrist monitor/matching the chest sensors when running. Where it goes a bit odd is when I swap to an indoor rowing machine where it struggles to show my heart rate above 90 bpm . in a 30 min workout at 28 strokes per min my average heart rate was 81 and maxed at 97. clearly pants. Given the discussions I will retest with a chest strap.

The Garmin VO2 max calculation is also a bit of a mystery. but that's another story /thread!

[ktsok in reply to seaspaniel]

Let us know how the rowing heart beats! 81 doesn’t seem at all right. Unless sea spaniels are just reallyyyy relaxed on (virtual) water?!

[seaspaniel in reply to ktsok]

It will take a week or so to sort as I have a weekly schedule, plus working out contemporaneous HR readings. I am a qualified statistician so no doubt that will go pear shaped.

As to rowing, I enjoyed rowing at school and still row the same way on a machine. Ie I feather the oar/handle! Looks odd but it’s effective. Usually get through 2km in about 7mins

[theoldfellow]

Curiouser and curiouser. I have been looking at my Garmin records. There are definitely times when the HR jumps (and that's the only word for it) to or from synchronisation with cadence. I see 'cliffs' in the record. I don't think hearts work that way. I'll try a tighter strap.

Garmin thinks my VO2 Max is 42. At my age (69), after 50 years on the couch and then just 18 months regular running?

Thanks for this thread ktsok .

[ktsok in reply to theoldfellow]

No worries! I don’t know if ‘cliffs’ are how hearts work or not... an adrenalin spike or sudden increase in effort would probably look cliff-like?

As for Vo2 max, it probably isn’t a million miles away? Bask in your score! Mine got up to 44 at one point (43 here) but it’s sunk to 39 since my month off running.

[backintime Graduate10]

I loves this thread. I don't have a watch....yet. I have no knowledge of my heartbeat either. O went to the doctor last week and he took my heart rate and blood pressure and didn't gasp or say oh la la so I am guessing it's ok. That is the extent of my knowledge

[ktsok in reply to backintime]

Haha. Maybe that’s for the best! All this tech stuff isn’t necessary, or necessarily accurate, but I do love a gadget and like info, so it (usually) adds to rather than detracts from my personal running experience. But I can imagine it would be an irritation for others!

[Katnap Graduate10]

Thanks for posting your results ktsok. Those HRM numbers seem much more sensible.

🐱 Katnap 🐱