Huge discrepancy between Fitbit (Charge 3) and Polar (H10)

[Weighttolose]

Hello. So I have compared my Fitbit (Charge 3) with my Polar chest strap (H10). Both report a similar heart beat at low activity levels. But when I start running my Fitbit Charge three can shoot up to 160 to 170bpm (220 minus my age would get me to 170) quite quickly whereas my Polar chest strap would report 110-120. I have changed wrists, used a new Charge 3, and tested alternative tightness of the wrist strap -- the huge difference remains. So I tested a new Polar chest strap (H10) - same result. I even had a cardiologist administered stress test (no problems noted) where the stress test numbers were aligned with the Polar chest strap but far off those of the Fitbit. The gap when I run can be as high as 70-80bpm -- it is huge! What is going on? Any ideas? Thanks.  

[nasacpa]

Based on my experience, a FB doesn't always work well as a pulse monitor.  When I look at my activity graphs after a walk, many times FB records my heart rate at 180 bpm for awhile, then drops back down to where I think it actually should be.  

If I were actually at 180 bpm, I would be breathing hard, and sweating a lot more.  My walks are done in the Houston, TX area (flat as a pancake), and I'm not walking upwind.  My pace stays pretty much the same throughout my walk (generally 90 minutes).  

This discrepancy has not ever occurred outside of my walks.  I have reset my FB numerous times, but the error keeps occurring.  I've just resigned myself to using it as a pedometer, and to monitor my resting heart rate.

[Dominique]

You are comparing an activity tracker (Fitbit) designed to be worn 24/7 to a sport watch (Polar) designed to be worn during your workouts only. Also wrist-mounted tracker vs. chest strap. The discrepancy during high-intensity effort is to be expected.

[checking]

@Dominique Are you saying that Fitbit makes no models that work well for vigorous exercise workouts because they refuse to acknowledge the limitations of optical heart rate detection? BTW - I think my 'sports watch' (Fenix) is intended to be worn 24/7, and can use data from any industry standard ANT+ heart rate sensor..

[Dominique]

@checking : first of all, note that I only speak for myself, not Fitbit. Secondly, I have no experience with Garmin products, including the Fenix. I’ll note that the list price of Fenix 5S starts at $499.99 and that of Fenix 5X at $599.99. Depending on what extra features are selected, models can get more expensive. Charge 3, OTOH, has a list price of $149.95. That being said, if your Fenix does everything you expect it to do, by all means use it instead of a Fitbit.

As to Fitbit "refusing to acknowledge the limitations of optical heart rate detection", why should they? Did they make claims that the technology they use for HR monitoring is better / more accurate than that used with chest straps? 

Companies don’t need to be all things to all people. Fitbit probably caters for a different segment of the population as Garmin, Polar, Suunto, Apple etc. Everyone must pick up the product that best serves their own needs.

[emili]

discrepancy aside, how is an adult averaging 110 HR while running? that is incredible. I am a 49 year old woman, on the low side of the weight chart with low body fat. I work out everyday and run a fair amount. I have never run with an HR that low. The lowest when I hit steady state is 150. I also had a polar chest strap back in the day and my charge HR (yep going back years) was always aligned with it. I haven't tested it since, but I would think that technology wouldn't get worst. I can also say that doing the same activity with a charge hr, charge 2, charge 3, alta HR, both versas and the ionic is exactly the same. so even if it isn't completely accurate, the discrepancy is consistent which gives me the data I need to manage my fitness. I am suggesting that even if the C3 is higher, it will be consistent and you can still get data that is useful. 

[Weighttolose]

Thanks to everyone who responded - much appreciated. I cannot explain the huge discrepancy between Fitbit and Polar (and it is worrying). But not much I can do about it. I do think that the Polar strap is likely the more accurate (as it is a chest strap) and most of the research I have seen supports chest straps over wrist watches for high intensity training. Yes my heart rate is low - always has been. Doc says I am fine. I hope so. Cheers all.

[Weighttolose]

Thanks - much appreciated. I cannot explain the huge discrepancy between Fitbit and Polar (and it is worrying). But not much I can do about it. I do think that the Polar strap is likely the more accurate (as it is a chest strap) and most of the research I have seen supports chest straps over wrist watches for high intensity training. Yes my heart rate is low - always has been. Doc says I am fine. I hope so. Cheers.

[t.parker · Accepted solution]

@emili optical sensors may get inaccurate due to the motion and while running very often they pick up a cadence rather than HR. It's not only Fitbit suffering this problem. The wrist is moving, bending, legs are generating more tremors - all of it produces some kind of noise which may overpower the actual HR signal. I'm not sure what your cadence is but you may try to compare HR and cadence if you use any other device that supports cadence measuring. If you are looking at average HR it may be mixed up with cadence and in the end, produce the wrong result. This is a limitation of the technology. Now, other devices may pick up HR better, others worse. It depends on things like device size, weight, number of LEDs used, the shape of the tracker, how it is worn etc. Even between one manufacturer's devices, such factors will bring inconsistencies. There is no other way of fixing it but supporting external sensors. Here's an interesting article explaining how the HR signal can be affected by a person motion:

https://theconversation.com/how-reliable-is-your-wearable-heart-rate-monitor-98095

[Weighttolose]

Very helpful - thank you!

[Fizzyjelly]

The answer is for Fitbit to talk to polar and glean the stats from it in the same way it does with MyfitnessPal. 

[t.parker]

Most of the competitors watches can connect directly to chest straps and other sensors. When training, I don't use wrist HR because regardless brand, it won't be accurate enough. The fact that I have a choice is a selling point to me.

[Perris4125]

Definitely is an issue at higher HR’s.

Ive recently gotten back to running intervals on my home treadmill & the FitBit HR3 is consistently 20-30 beats higher. My perceived exertion more closely matches my Polar F7.

In any event I do agree with one commentor saying that the Fitbit is meant to be worn 24/7 and cost $150 for a great activity and sleep tracker. If you are very serious about running or other activities that raise your heart rate into your higher zones; you need to have a specialty watch and just wear your Fitbit on the other wrist! The Fenix is great, but HUGE, not sure if I would wear it to bed or with my dress clothes.

[Fizzyjelly]

I've found there is more accuracy if the Fitbit is worn higher up the wrist

[Perris4125]

I will try it.

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[Perris4125]

Maybe because it’s tighter?

will try it Thursday and report back