Heart rate inaccurate

[Bluekona]

I have the new blaze and am pretty happy with it overall.  I had an HR prior to the Blaze.  The only thing that I do not like is that I cannot get either FitBit to monitor my heart rate accurately while I exercise intensly.  When I am lifting, I wear a Polar Heart Rate Monitor with a chest strap.  My Blaze does not come close to the Heart rate that the Polar shows.  I have been extremely active for my whole life.  I count my HR manually.    The Fit Bits are dangerously inaccurate.   My average HR while lifting is over 120 with a max of over 160.  The blaze only measures an average of 95 and a max of 120.  The inaccuracy throws off my calorie count for the day.  I slide it up and down my arm trying to find a sweet spot.  But, no matter what I do I cannot get an accurate heart rate until my HR drops below 110.
Strangely, it seems to be fairly accurate when I am hiking intensly.  It comes close when I use the eliptecal cross trainer at a moderate level.  However, if I do HIIT it will not measure correctly.  I really don't know how to get it to work correctly when I am lifing weights or working out hard.

[SunsetRunner]

I find the HR tracking to be fairly good on both the Blaze and my previous Charge HR. I was skepticle at first so I used several methods to test. At the Gym on the bike I used the hand grips to check my Pulse and then looked at the watch and they were both within 1 to 3 beats per min. I then made use of the Galaxy S5 built in system (finger over the flash) using SHealth and it too was almost the same as the other two.  Now it maybe that my chubby arm allowed for better contact, but for me the Blaze seems to be a good indicator.  I even did the manual pulse check for 10 secs X 6 and it too game out close to the same.

Admittedly there are times when the watch can't read the pulse, but I put this down to the fact that it can't read it because I'm dead for a min or two now and then so of course there is no pulse to read, so when I can't get a reading on the blaze and just slap myself on the face and all is good, although I do get odd looks from the other gym members although for the life of me I can't figure out why.

[AdamMSC]

Lololol! Good to see that other people are finding it to be fairly accurate as well. It's odd because there are people like you and me who haven't had huge problems with it and find it to do a good job, and then there are people that are getting consistently bad readings...

[Tyler91]

Follow up to my previous posts.  I returned my Blaze and picked up a replacement. Tonight I was able to check to see if the heart rate tracking was working better with the new one.  It appears that it is better.  I believe the tracking is correct (screen shot below...compare to previous post above.)

My conclusion is that I had a faulty model.  Fingers crossed that I don't experience any more issues.

[AdamMSC]

Nice! I got the chest strap in yesterday and compared the two. The link is below:

https://community.fitbit.com/t5/Blaze/Blaze-vs-Chest-Strap-polar-H7-A-review/m-p/1240131#U1240131

[FSDrew]

While on an eliptical, the HR measured by the machine itself read nearly identical to what my Fitbit Blaze read. No matter if my HR was up to 180+ or as low as 140 during the workout, the eliptical machine and the Blaze were reading the same. I realize chest straps give the most accurate readings, but I would assume the readings of the eliptical and Blaze must be fairly accurate, since they were reading the same HR. I do wear my Blaze higher up on my arm, two to three fingers above my wrist bone while working out. 

[AdamMSC]

Interesting. I bet the difference in what we are seeing is the way you got to 180 bpm. It was probably more gradual than a high intensity, 30 second rope jumping session. When I was jumping rope I was going from a low- medium heart rate to an overly elevated one within 10 seconds.  That's where the Blaze and other wrist-based monitors seem to have trouble. However, it was RIGHT on while I was on the treadmill, and I would assume it would continue with that trend as my heart rate went up. I am going to give it another go in a bit and will come back with more results. This time I will do a gradual increase in cardio until I reach those higher zones.

[Mwillis]

I have also experienced a bid difference in HR that the blaze shows and other devices. Today I tried moving the watch face to the other side of the wrist and the HR functioned much better. So you may try moving the watch back to the underside of the wrist and see how that works. The same place a nurse would hold her finger on a manual her test.

[Mississippirn]

I have the same problem.  When I am on the treadmill my HR registered 68 on my fitbit but 108 on the monitor on the treadmill.  I am walk at a fairly fast pace and know that my HR is higher than 68.  I thinking about sending mine back because the HR monitor is the main reason I bought the Blaze as I am a heart patient and need an accurate HR or close to it.

[Mississippirn]

If it is not going to give you an even close to accurate heart rate it is pointless to have it on there and charge for it.  Because why pay for something you can't count on. 🙂

[tassiegirl01]

I am wearing my blaze higher up on my forearm (glad I bought the L size!) and it's generally very accurate even when doing weights or HIIT.

Where I have found it to be odd is that I will often see my heart rate is 60bpm on the Blaze, but the "RHR" displayed is 72 or higher.  How can my RHR be that high, when my heart rate is frequently at 60 or lower when I'm sititng at my desk? There must be a bug in the algorithm? I wear the blaze to sleep 85% of the time which appears to have no implct.

[Kaloria]

I have similar issues with my fitbit Blaze.  I was wondering if it could be due to residue on the back of the Blaze.  Is there a suggested way of cleaning it?   

[JamesB271]

Just jumping on the bandwagon. My fitbit blaze heart monitor is very inaccurate when weight-lifting, and always low, usually by 30 bpm or so. It is also low when cycling.

But, during a fast walk it is often high, once again often by 30 or even 40 bpm.

On the plus side, as long as my actual heart rate is below 100 bpm or maybe 110 bpm it is very accurate. And the step count is excellent. So for tracking steps, heart rate, and calories during general daily activity, up to and including walking at a moderate pace, it is very good. As it now well known, it has problems with high intensity exercise.

On the whole I am happy with it. For $200 it does a lot and you cannot really expect medical grade accuracy.

[bcalvanese]

Here is a comparison between my Blaze and my Garmin fenix3 with a chest strap monitor...

https://community.fitbit.com/t5/Blaze/Comparing-Blaze-To-Garmin-fenix3-walk-activity/m-p/1390051#U13...

I am getting pretty accurate results with steady state cardio stuff.

[Bill45]

I'm 71 YO and play pickleball about 8 hours per week. For those who don't know, pickleball is sort of like tennis on a smaller court. I have found that my Blaze is accurate if I set the exercise to TENNIS. I've checked it a couple of times vs my Polar FT7 with chest strap and both the average and maximum heart rates are within about 2 BPM. Typical averages are around 130 and max around 155-160, with a lot of up and down HR. This is for 1 to 2 hours of play. If I forget to set the exercise to TENNIS then it is highly inaccurate. It reports averages of about 95 and max of around 110. Sometimes it counts it as SPORT and sometimes it doesn't count it as any exercise. This is for the same level of exercision. Perhaps it sets the sensitivity higher if an exercise is set. I can't think of any other reason for the huge difference.

I also bicycle, with about the same HR range as pickleball per the FT7. It reports much lower HR than the FT7, even if I do set it to BIKE. I think that it is inaccurate for biking and weights because of pressure on the hands and perhaps that affects the circulation. It seems to report accurately for a walk if I set it to WALK or not set it. Perhaps this is because my max is rarely above 110. I can't get my HR up much higher than that because I get tendinitis if I try to walk too fast.

[JamesB271]

Interesting post that makes a lot of sense. With continued observations of my Blaze I can confirm the finding of others that it does much better with steady state exercise. It is the transitions where it seems to go wrong. And it is never very good with cycling.

But with fast walking it is good in steady state up to fairly high levels, like 130 bpm or so.

Your tip about setting the exercise type is interesting. I will give it a try.

[SunsetRunner]

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@JeffWski wrote:

(during my first cooldown section) My Blaze actually increased from 130 to 160! That's absolutely wrong. Obviously my HR went down during the cool down.  2 out of the 3 cool downs the Blaze HR went up instead of down. 

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I'm incredibly frustrated, relieved, puzzled and I don't know WHAT that someone else has experienced this phenomenon; a SPIKE in HR during COOL DOWN. At the time, I felt nothing difference but to see your HR allegedly approach 200 bpm on the graph was scary.

So this is a known issue?

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[Caimantra]

I'm having the same issue. When hiking, the measurements are corresponding to my effort. But the issue seems to appear whenever my hands are involved in the workout such as holding the bars when riding the bike or using workout equipment or when doing push-ups etc. And the measurements are significantly off. E.g. we have this rather steep hill coming up to our house. When I'm riding my bike, I'm completely out of breath, can feel my heart pounding heavily etc. but my blaze is giving me a heart rate of 115. It does not seem to come from an ongoing movement of the hand (like bending it back and forth), but from the mere involvement such as holding something. Like many others here in the forum, I've tried to reposition the blaze, wear it tighter etc., but to no effect.