Charge 5 heart rate shows spikes

[mikerophoto]

I love the Charge 5 but it occasionally shows strange "spikes" in the heart rate readout following no change in activity level (118 to 170 bpm). I tried wearing a quality chest strap in addition to the Charge 5, and the strap does not reflect these spikes. I often feel "lightheaded" during these spike periods. What is my Charge 5 reading and should I be concerned? I signed up for notifications  concerning irregular activity, and have received none after a few weeks.

Moderator edit: format

[DavideFitbit]

Welcome to the Community forums, @mikerophoto.  

Thank you for sharing this information about the inconvenience you've been experiencing with your Charge 5. 

Before considering other options, I recommend that you try restarting the device again using the three pulse restart method mentioned here below, instead of the restart option found on the Charge 5 itself: 

1. Connect your device to the charging cable. For instructions, see How do I charge my Fitbit device?
2. Press the button located on the flat end of the charger 3 times within 8 seconds, holding each press for about 1 second.
3. Wait 10 seconds or until the Fitbit logo appears.
4. If the device doesn’t restart, wait 15 seconds to try again.

In addition, please follow the instructions in this article to improve the accuracy of heart rate information and check the information mentioned here about other factors that could affect your heart rate reading, this has been useful to other users who have experienced something similar. 

These steps are usually helpful with any accuracy issues you may experience. If you only say these spikes once, it's possible that it was related to a problem with accuracy with the device, but in case you've seen other abnormal heart rate spikes and you can see them in your chest strap as well, I do recommend that you consult with your doctor, since the Charge 5 is not a medical device. 

I'll be around. 

[mikerophoto]

Thanks very much for your response. The heart rate spikes I experience
happen frequently, but sporadically. During the summer months there were
very few occurrences. Many of these spikes are accompanied by a slight
lightheaded feeling that only dissipates when I rest.
The Polar belt shows a mild increase during these episodes but usually not
above 90 bpm. I have reset the Charge 5 many times and even bought new
devices frequently. I saw my doctor and had a full range of heart tests at
the end of last year. I am seeing him again on Thursday. For some weird
reason, when I do even strong workouts on my treadmill, it does not occur.
I have read the information you referenced at your site. I have also
reduced arm swing, changed to my left arm, stopped chewing gum, and turned
off my music device with no change in the spikes.
Fitbit has been a key reason for my recent health improvements. Over
three-plus years, I have lost 40 pounds and reduced my resting rate from
80-plus to 57 bpm! I walk 9 miles, 7 days a week. I am 72 and retired.
I will attach a sample screen. No change in pace or intensity occurred
during these jumps. I am simply searching for a possible explanation that
you Fitbit experts may have seen before.
Thanks again for helping....Mike

[DavideFitbit]

@mikerophoto Thank you for your reply and for sharing all these extra details. 

Since you continue to see the heart rate spikes you mentioned, even after all the troubleshooting steps suggested earlier, I've gone ahead and sent your information to the Customer Support team for further assistance with this, so you should be getting a reply soon. Please keep an eye on your inbox. 

Thanks again for sharing all your comments and feedback about this. 

[Barthome]

Mike,

Very late to this thread. I am experiencing the exact same symptoms.  I have spoken with my doctors, both GP and Cardiologist with no answers. I believe th device is picking up another "signal" and interpreting it as a heart beat. Did you ever find an answer. 

Thanks.

[mikerophoto]

SERIOUSLY?????

Mike

[Barthome]

Yes I am serious.  So much so I went out and got an Apple Watch. The detection technology is essentially the same as

the Fitbit. I get "spikes" on the Apple. Did you ever get an answer ? 

[MizzT]

I am experiencing the exact same thing!  It's happened a handful of times on my treadmill when I'm at the end of my workout and cooling down at 2.5 to 2.0 mph my heartrate spikes to 170 to 180 from 110 to115.  I just had an echocardiogram and all indications are that my heart is fine.  

[mikerophoto]

Same issues for me…had the full EKG & stress tests. Only explanation; bad input from the FitBit 5! I now do the two-fingers-to-neck heart rate count and it’s always in a safe range and nowhere near the FitBit reading!

Mike

[Barthome]

Same. But I get the same event on both my Fitbit and my Apple Watch. My Fitbit is a Charge 5. When I check my blood pressure manually I get the same feedback. BPM is fine, no where near the device readings. I have read up on the technology on how the devices record heart beats. I've asked my cardiologist and he is interested but has no answers. I know something is being picked up but so far no one can answer what.

[earlydays]

---

@MizzT wrote:

...when I'm at the end of my workout and cooling down at 2.5 to 2.0 mph my heartrate spikes to 170 to 180 from 110 to115. ....  

---

I've not had such a large jump, but I do find during say a 30 to 50 minute workout (indoors - a mix of weights, push ups, sit ups, squats, lunges, etc), I seem to get a small but noticeable increase in readings each time I stand up when switching between the various different exercises within the workout - and a noticeable drop in readings when I'm doing the individual exercises!

 And then when I finish, now cooling down and amble just a few paces to the sink to wash my face, that's when I then tend to see the highest readings of the whole workout!

So much so I feel that if I were to take the fitbit heart rate readings as gospel, the most effect part of the workout seems to be the standing still between the actual exercises or washing my face! Perhaps I should forget the lunges, sit ups, push ups, squats, weights, and just stand still for 50 minutes to make the workout more effective!

I'm reasonably convinced now that this is down to really, really poor hear rate sensing by the unit. When I start the "workout" exercise (manually) on the unit, even before I start moving at all, it's often already showing my heart rate as "--" even when the home screen was happy to show a heart rate number. I've seen it take around a minute after manually starting the exercise in the workout app on the unit before the "--" goes away and a heart rate number appears, but when I look at the chart afterwards, this gap has been filled in.

I also notice when I'm exercising at constant pace, I sometimes see the heart rate numbers ticking down perhaps 10 or 20 BPM down, and then "--" appears for a short while before the numbers then tick back up. At other times I see a similar down tick, expecting it to go to "--" but is then starts ticking back up before the "--" appears, but the down tick makes no sense in relation to the exercise I'm doing. I strongly suspect it had lost the reading, but wasn't admitting it.

In my workout earlier today, the numbers seemed a little low for how much exertion I was putting in, so I waggled the unit on my arm while briefly standing still, and the heart rate number then ticked up 10 or 15bpm or more.

Taking it all into account, I've come to the conclusion that my unit at least is just really, really poor at sensing heart rate, and behind the scenes the Fitbit "algorithm" is doing a huge amount of smoothing and interpolation to fill in the quite huge gaps - gaps of a minute or more at times - where it hasn't been able to get an acceptable reading.

In essence, I think in these cases, because it's doing so much averaging and soothing when the reading is poor, it's struggling to realise that my heart rate is higher - basically because it's smoothing / averaging with minutes old data that it last properly read, which was potentially before I got going

My (strong) suspicion is that the moderate spike I see when I stand up between exercises, or when I've finished and stand up normally, and walk to the sink, I think the fitbit is now just getting a more stable reading at that moment.

So I think this is perhaps why I see my reported heart rate go up in the minute or two after I finish my workout, rather than down.

It's not so much a spike when I finish, rather I think it was likely under reporting my heart rate because of poor detection while I was physically doing the exercise.

Which, as a result, doesn't give me any confidence that the reported calories burned number is going to be all that accurate.

I'm still trying to put together the evidence before posting my own question on this, as this is the first tracker I've used, so I don't know what I reasonably should expect from these type of fitness trackers.

But so far, after having it for only a few weeks, I'm not impressed at all.

[MichaelFlatters]

This sounds like what happened to me tonight. Went out on my first walk after a long hiatus and substantial weight gain. Was taking it easy pace wise and after about a quarter mile was in the 125 bpm zone. (I'm 59 years old so 75% to 80% of max). After about another quarter mile i checked my Fitbit and it was reading 183. Holy crap, I thought. I stopped and manually checked my pulse and it was right around 123 bpm. It continued fluctuating between 172 and 183 for about 10 minutes. Then as quickly as  it happened, it dropped back down to the correct rate for the rest of the walk. I just did the button on the charger reset and we'll see if it does the same thing tomorrow night.