Heart rate graphs don’t match

[MelissaCamille]

I recently upgraded to a Charge 5, and consequently got upgraded to zone minutes (not a fan). While looking at the heart rate graph in zone minutes, I noticed it was different from my regular heart rate graph. For instance, there is a big spike at around 2am while I was sleeping, and then a large gap in data. Neither of these are present on the regular heart rate graph. Anyone know why they aren’t the same? Shouldn’t they be? This is going to make me crazy on top of how crazy the new heart rate reserve zones are already making me...

 

[LZeeW]

@MelissaCamille   I can tell you this about the two graphs.  You regular heart rate graph shows numbers that are averaged over five minutes.  The zone minute graph is average over on minute.  This is why the regular heart rate graph loses some of those big spikes.  I don't have an answer for the gap.  You might have been sleeping with your wrist in an odd position, with a "weak" heart rate signal.  The regular heart rate could fill in the gaps because of the sampling time, but the zone minutes couldn't (wild engineering guess).  Premium users get a sleeping heart rate graph, also sampled at one minute intervals.  Sometimes my sleeping heart rate will show a flat section and the other graphs have normal shapes.

Changing to a zone minute device is a real eye opener.  I might not be able to make you a fan, but I hope I can make you less of a hater.  The CDC and WHO have physical activity recommendations that are classified as moderate and vigorous activity.  The CDC heart rate zones are 64% - 76% of maximum heart rate and vigorous activity is 77% - 93%, where they use the 220 - age = maximum heart rate equation.  Fitbit uses an equation that uses your resting heart rate in the calculation.  I like my Fitbit zones much more than my CDC zones.  Also, the CDC recommends 150 minutes of moderate activity or 75 minutes of vigorous activity or a combination of the two each week to meet weekly activity recommendations.  Cardio and peak heart rates earn 2x zone minutes.  Original active minutes just don't work with current activity recommendations.

[MelissaCamille]

Thank you for the reply and for pointing out the additional heart rate graph for sleep. The discrepancies are now even more confusing. 😆 The zone minute graph shows my heart rate bouncing between lows 60s to high 80s from one minute to the next last night, but the minute by minute sleep graph shows it staying below 70 for the most part, with only small variations. For example, at 4:42am the first shows my heart rate at 90 and the latter has it at 67. It can’t be both numbers and I’m left wondering if either is accurate. In addition, while still in bed and looking at all this, I suddenly earned 2 zone minutes while my heart rate was most definitely not racing at 129 beats per minute! I’m not sure what the issue is. I never had a problem with my Inspire. 

  

 

[LZeeW]

@MelissaCamille   I don't have any answer (good or bad) to explain the differences we see in the sleeping heart rate graph and the zone minute graph.  It's all the same data, right?  Generally, I don't try to explain everything my Fitbit does.  And I try not to worry about it too much, either.

BTW, I want to point out a portrait/landscape bug in the iOS app with all three sleep subtiles.  If you expand your sleeping heart rate and are looking at it in portrait, you can't rotate it to landscape.  But if you rotate it to landscape, THEN expand it, you will see it in landscape view.  It will rotate back to portrait, but not back to landscape.  This is the same for the sleep stages graph.  I rarely look at the time asleep bar graph, but it's there, too.

[MelissaCamille]

Now it seems a heart rate spike has been retroactively added at 1:03am that was most definitely not there when I did a screen shot this morning. 

 

Anyone have any explanation for this? Is there a remedy? I’ve had the Charge 5 all of 2 days and am finding the discrepancies incredibly frustrating. If I can’t figure out how to make it work more accurately, I don’t see any reason for keeping it. So disappointed. 😥

[MelissaCamille]

Thanks for the tip on getting the sleep graph into landscape mode!

[OlafBraxhoofden]

Hi Melissa, I am having exactly the same problems you are experiencing, also using a Charge 5 

[MelissaCamille]

@OlafBraxhoofden I contacted Fitbit support about it last night and they just had me check to make sure my app and iOS were current, then told me to wait a few more days to see if the problem was fixed. I tried to explain that I would want to return the tracker if it wasn't working properly, so waiting and wearing it for days and days just to see if it does what it is supposed to do was a problem, but they didn't seem to care. I decided to make another account so I could continue wearing my old inspire HR and compare the data. 

I'm finding that whenever I exercise, the Charge 5 creates heart rate spikes retroactively for hours before the exercise took place. I am also finding I get random active zone minutes while sitting and doing nothing that is actually getting me steps or raising my heart rate. But I guess Fitbit thinks this is a software problem and not a problem with the device itself. Very frustrating.

[fionac]

@LZeeWyes, but......

Back in the day when I had a Charge 2 (I think), Fitbit changed the way they measured active minutes.  When I first got the device it counted every time I rushed about so I'd pick up a couple of active minutes while nipping from office to lab and back and another few walking to lunch and a few more walking back and so on.  Then it was changed because the health advice was that to be effective active minutes had to be at least 10 contiguous minutes, so I only got them if I went for a decent walk which I found far more motivating.

Now they seem to have gone back to the older system (though using heart rate rather than METS, I think) and I pick up active zone minutes through my on-my-feet-all-day life.  I've picked up 9 so far today without feeling like I've done anything worthy of them at all.  I can pick them up when I'm stressed and the adrenaline is kicking in or when I'm knitting and feel that that's really not how they should work.

[fionac]

That's truly bizarre; I'm getting the odd random spike, but it's usually during the day and when I'm actually moving so I figure that it's just an oddity.  But having it happen at night when you're sleeping is very strange, unless you've got your wrist in a particularly odd position, but you'd have thought that it would have happened with your old device too.

[LZeeW]

@fionac   You're right about the active minutes.  Fitbit changed things up, depending on CDC recommendations.  For a while, the CDC had a ten at a time recommendation.  I already described the current CDC target heart rate zones for moderate and vigorous intensity.  These are very different from the original active minute heart rate zones.

Now about the odd spikes and gaps.  Optical heart rate tracking uses a technique called photoplethysmography (PPG).  There are emitters that give off the green light and sensors that sense the reflected light.  NEWS FLASH.  The wrist is one of the worst places on the body to do PPG optical heart rate tracking because of something called optical noise.  Yet we love the convenience of a wrist device.  This is why I don't fret the weird stuff that I see.  I have better Stress Management Scores when I stop worrying about the weird Fitbit stuff I see.

[fionac]

I have a similar attitude; I don't really get a lot of the angst around aspects of the device - it's a health tracker, not a medical device.  There'll be dodgy HR readings (though getting AZMs in the middle of the night would worry me), you get steps when cleaning your teeth or washing your hands, the GPS isn't the best but, on the other hand, it gets me out walking or running every day, I love the sleep monitoring and the new daily readiness score and I'm fitter now than I was before my first one, so I can take its flaws.

[MelissaCamille]

@fionac what’s so weird is the spike wasn’t there when I checked it in the morning and only showed up hours later after I had exercised. It doesn’t seem like data that has already been recorded should change for any reason. 

[MelissaCamille]

I understand taking the stance that the tracker should only be viewed as an overall health tool and not a medical device, it’s just been frustrating that this fancy new Charge 5 seems to have some weird glitch not present on my old Inspire HR. I wore both devices today and it was interesting to see the difference.

 

 

Both heart rate graphs mirror each other for the most part. There are some variations of around 10 bpm (not a super big deal). But there is one large random spike on the Charge 5 that’s 40 bpm higher than what’s shown on the Inspire HR, which, for me, just seems like too big a discrepancy to not be considered a malfunction with either the device or the software. I was sitting at my desk not doing much of anything when it was recorded. It does seem to have raised my resting heart rate by a point as well. 

 

 

[OlafBraxhoofden]

Melissa, I agree. I have also noticed on several occasions that spikes are added for moments in time that were hours ago

[MelissaCamille]

@OlafBraxhoofden it has to be some bug with their software. There is no reason for data that has already been recorded to change later. I noticed it seemed to be triggered by exercise. If I earned active zone minutes, a spike in heart rate would pop in the window when I'd been sleeping. I updated the app and my iOS, restarted the charge 5 and will check to see if it happens again today. I did try to ask their customer service rep about this, but they indicated it wasn't a problem they were aware anyone else was experiencing.

[fionac]

It is very odd.  I've just been looking at the data from the last few days and there's really nothing unusual in it - it trundles along fairly steadily except at times when I know I've been active; no anomalous spikes where shouldn't be!

I guess it's difficult if no-one else is reporting a problem because it'd be very difficult to isolate what's causing it.  

[JennyL265]

I have the same problem that the Target Heart Rate Zones graph is not the same as the regular Heart Rate graph. It is obviously not related to different ways of averaging the data or calculating the active minutes. The heart rate data from these two graphs are just completely different (especially during the night), and one graph is based on wrong data. Moreover, I don't get why they use different ways of averaging the data in one system. 

I'm a bit surprised that their technique staffs are so unprofessional to the data they collected. I am not expecting the data to be precise as medical device, but at least the data should be more or less correct.

[MelissaCamille]

It’s kind of ridiculous. I’ve taken to checking the graph first thing in the morning so I’ll know if there were any weird heart rate spikes that actually occurred while I was sleeping, or if they were just added later, as the graph for the time I was sleeping changes continuously throughout the day. Here’s an example, these are screenshots from first thing in the morning, afternoon, and evening on the same day.

Gaps in data appear, disappear, and heart rate spikes grow out of nowhere. It makes no sense for recorded data to be changing like this. I’ve contacted fitbit multiple times about this, and done everything they’ve asked me to do to try to fix it, with no success. They finally said they were forwarding the problem onto a higher level of support and would be in touch, but I haven’t heard anything and it’s been almost a month. Very frustrating. 

[melonjam]

A friend has just drawn my attention to this. I don't tend to look at the HR zones graph, but I also have on days where I have active zone minutes that a spike of active minutes appears in the early hours of the morning. As does my friend.