Fix *optical* HR and chest strap HR issues – Troubleshooting Garmin, Polar, TomTom, Suunto

What! A heart rate of 280bpm, that can’t be right can it? Oh hang on a minute now there’s no reading at all.

Most of you have been there with Garmin HR straps. It’s annoying when the readings are wrong especially if you train by heart rate. Luckily you’ve just bought an expensive, optical HR device for your wrist – or maybe even for your upper arm or ear. Let’s say ‘wrist’ for now. Surely new technology can only make accuracy better?

suunto spartan sport whr valencell

Nope. More than likely the optical situation will make matters worse for the general population and their optical HR woes.

Anyway DC inspired me to update an old post of mine with lots of lovely 2017-opticalness.

OPTICAL HEART RATE ISSUES – FIXING

I thought I knew what I was doing with chest straps. I didn’t have many problems that weren’t easily solved by buying a new one. Conversely I might wear one optical heart rate device with no problems for a while and then a new model arrives and I wear it in EXACTLY the same place and do the EXACT-SAME sporting things…but the HR readings are rubbish.

There is a lot going on here and I’m not convinced that anyone quite understands why sometimes things just don’t work with optical HR.

2x Epsons Optical Sensors

You’ve probably read about these:

  • oHR can sometimes be tricky on darker skin
  • oHR can sometimes be tricky on hairy skin
  • oHR can sometimes be tricky if you have a higher fat content on your lower arms
  • oHR is affected by blood circulation (it takes the reading from bouncing light off blood…so there must be blood)

So the solutions are simple: lose weight; don’t get a tan/change ethnicity; cure Raynaud’s syndrome; and shave your lower arm hairs! Not very helpful, sorry.

MIO Fuse Review - Optical Sensor

MIO Fuse – Optical Sensor

The quality of the sensor is important and these are some of the factors that go into making a good piece of hardware:

  • Colour(s) of the LEDs
  • Spacing of the LEDs
  • Shielding the shone and received light from interference of other light sources of similar wavelengths

But, perhaps even more than that, the watch/sensor manufacturer will most likely have to add a mathematical algorithm (software) to deal with: the swinging of your arm; the flexing of your wrist; and the particular bounce-type of whichever sport you are doing. Yes the algorithm will probably vary from sport to sport.

1st TIP: Use the right sport profile or just stick to the sport profile where it seems to work best

Clickable: Example or errant optical HR readings from Garmin 5X

You will no doubt have read the user manual that came with your errant watch. It will likely say something like “wear the watch 1cm from the wrist bone and wear the strap tight but not too tight to leave mark”.

2nd TIP: Wear it tightly 😉 and If practical wear it further from the wrist.

But I’ve found that even when wearing it in the ‘right place’ (1cm from your wrist) that the blooming thing can slip down back to the wrist. Yet, as alluded to earlier, with some devices this causes no problems but with others it does.

3rd TIP: Try the other arm to find a bit more watch-strap friction

Polar A360 Review

Polar A360 vs Samsung Gear Fit Optical HR

In some of my more ridiculous moments I have pounded the streets of SW London wearing several watches. This is not a good idea. As well as the watches banging into each other and ruining the optical HR signal I have heard that it is possible for one optical LED from watch to affect the sensor on another watch and they do not even have to be next to each other/ maybe the light goes within the body or directly through the air. Someone with a grasp of physics can clarify that one for me.

4th TIP (just for me) only wear one optical HR device per arm or even just one in total.

So with all this ‘pounding’ going on, what personal factors could make that pounding worse? Maybe if you have a heavy impact when you run that could be a factor but maybe even the weight of the watch could be a factor as a heavier watch could move about more than a lighter one? This might explain some of my recent Garmin Fenix 5X woes – beautiful watch but heavy and I’ve not found the oHR as good as other, earlier Garmins like the 735XT.

5th TIP: Run lightly and avoid bumps in the road

Garmin 735XT Optical ELEVATE

Garmin Elevate – Pretty Accurate In My Experience

More recently I’ve seen some issues with optical HR devices seeming to take 15 to 30 minutes to ‘warm up’. Maybe it’s me warming up 😉 and getting the blood flowing.

6th TIP: Cover every angle of warming up – from a proper physical warmup to wearing the device before your exercise to ‘get it warmer’ and maybe even try recording a pre-run 15 minute dummy session.

That’s probably covered most avenues. If you have any other suggestions MANY other people will gratefully receive them. Thank you

7th TIP: Buy a chest strap 😉

CHEST STRAP HEART RATE ISSUES – FIXING

But on that note there are problems with chest straps too. I generally don’t have any problems with straps less than a year old. For some of the older Polar/Suunto/Garmin straps it was often either the STRAP (not the pod) or the BATTERY that was the cause of the problem rather than the physical ‘HR ‘pod’.

Firstly there could be a fault with your STRAP and/or your heart rate SENSOR / POD. I think that is unlikely in most cases where you have relatively new equipment.

Secondly if you have ever used a Garmin HARD strap you will probably have never found any problems. So that shows that the problem probably does not lie with the watch. If, like me, you may have bought a POLAR soft strap to which the GARMIN POD fits you will probably found the same level of HR spikes and dropouts in similar circumstances. Therefore this suggests to me that there is nothing inherently uniquely wrong with Garmin’s design.

Garmin HRM-TRI (HRM-SWIM) Review

Garmin HRM-TRI (HRM-SWIM) Review 4iiii Viiiiva Wahoo TICKR-X HRM-RUN

It’s just that soft straps for some reason are more prone to the sort of behaviour we are talking about. Why? If you look at the reverse of the strap you will see that the smooth ‘rubber’ contact area may be smaller on a soft strap.

This post is an updated version of (this) post from 2013:

Yesterday I had a turbo session indoors. Nothing too hard but a bit sweaty nevertheless. Immediately afterwards I went for a slow run in the freezing cold. Within 5 minutes I had incorrect HR readings. I had stopped sweating and some of the sweat already there had dried out. This to me VERY strongly suggests that the problem is related to the contact between the body/chest and the strap.

In really cold or really dry weather you may well find you are more prone to spikes. This could be because both hot and cold weather can have less humidity (humidity might be a factor). Or it could also be the case that when really cold you might not sweat much or when really hot and you are not trying much the sweat very quickly evaporates.

Similarly in early Spring or late Autumn/Fall when I am wearing thin clothing and cycling quickly I find some instances where I lose a HR signal and attribute this to the air movement causing all the sweat to evaporate and dry my skin.

Polar H10 H7 suunto smart belt movesense garmin hrm-tri hrm-swim

Either way a wet strap helps.

So if you lick your strap before any exercise you will probably find an improvement.

8th TIP: Lick it!

Polar H10 H7

Lick the shiny black rubber pads on the rear of the strap

Furthermore if you thoroughly wet the strap, you may find yet more improvement.

Garmin recommend that you use medical grade gel. I bought some and found that saliva was just as effective BUT saliva would more readily dry out in certain conditions.

Well 30 minutes after posting the original article I got this from Cy Gearing on FB:

Cy Gearing :: I use the garmin soft strap and use a gel from amazon. I don’t sweat a great deal so had issues, but been using the gel for 3 months now without dropouts. It cost the vast sum of £3.05 for 2 x100ml bottles and you need so little that I’m sure they will last at least a year!

So this I think backs up my assertion that it is a contact problem rather than static or faulty devices. Although Cy has obviously found that gel makes a significant improvement (well if 100% counts as significant!).

UNUSUAL (9th) TIP: Take out the battery and put it in the wrong way. Then put it in the right way.

However static might be a cause. BUT two different materials are required for static to happen (physics). This could be different shorts and shirt. Or it could be the soft strap and your shirt rubbing together. It might also be linked to static from body hair. I’m not convinced about this explanation but it is possible. I still have problems when ‘topless’ on my turbo. Static absolutely CANNOT be the cause in that scenario. Although it might be a contributory factor in other scenarios.

Finally you need to wear it in the right place! The centre of the pod goes over your solar plexus just below your rib cage. This is easier said than done for some people who find it extremely hard to get the chest strap to stay in the right place and, in fact, one of the reasons why lots of people  buy the optical HR devices we started talking about at the top of the post!.

10th TIP: Wear it in the right place or buy an optical HRM…oh dear 🙂

 

11 thoughts on “Fix *optical* HR and chest strap HR issues – Troubleshooting Garmin, Polar, TomTom, Suunto

  1. Other than battery low voltage failure, I presently have been using Spectra 360 Electrode Gel. It is cheap and easy to put on the Garmin and Suunto HR chest straps. With the Suunto, I get almost no dropouts or high readings. Bluetooth. With the Garmin, I get high HR when sprinting at the end of my runs. Ant +. My average HR is within two beats between both watches.
    I wear both chest straps for all my runs. With Garmin strap under my pecs and the Suunto strap about two inches over my pecs. Seems to work well. I also shortened any thick hair over where the pads are touching my skin.
    I am too cheap to buy a watch using OHR. My 910XT and Ambit3 Sport are good enough for me.
    My limit is under $200. for a used or refurbished sports watch.
    And with the STRYD Foot Pod I get POWER using the 910 in Bike mode and Ambit3 in Run Mode.

  2. The Suunto and the Addidas ( same snap spacing as Garmin ) have different snap spacings.
    Also Suunto uses Bluetooth while Addidas/Garmin use Ant+.
    Is there a dual strap that would accommodate both HRMs ??

      • Thanks for the heads up. I guess two straps will be my norm for now.
        Back to the original post about OHR. If you put the band on tight, I believe within a year the non-buckle watch strap will begin to tear and break. Replacements watch straps from China are cheaper then from Garmin or Suunto. My 910XT is in its 2nd strap.

        • good point. a strap like the ‘plastic’ fenix 5 one should be ok but something like the rubbery Spartan ones I suppose will be limited in their longevity

  3. Try a dual sensor Decathlon Kalenji CardioSmart sensor (made by Cardiosport) without strap ref. 3608429896289 19.90€, there is also a version with strap for 35€

  4. I don’t think i’ve ever had an issue with HR while using ANY of the chest straps I own (H10,HRM Tri,Tickr X) and I use the Spectra 360 as well. I think I paid 15 bucks American for like 9 bottles worth. A dab on each pad and you are good. As for comfort, the HRM-tri and H10 are super comfortable to wear (the H10 is the more comfortable of the two in my opinion) the Tickr though, not so much.

    As for reporting, I’ve used each on the same HIIT workout and found the H10 and Tri to be nearly identical, with just natural variants to my health. Each come off smooth on the chart (I use the Graphical HR widget on my F5 during workouts). The Tickr reports the same eventual information at the end, but is a blocky mess during the routine.

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