Gaps in heart rate at night

[Sianyy]

I've been having a recurring issue with my charge hr since I got it a month ago.
Not every night but around 3 nights a week it shows a gap in my heart rate for 20mins and then a spike to about 120bpm straight after before everything returns to normal.
Does anyone know why this might be happening? Is it likely to be an error with the fitbit reading or more indicative of a heart issue?
I do have tachycardia and ectopic beats but my last 24 hr ecg showed no issues
Thanks

[SunsetRunner]

Welcome to the Fitbit Forums @Sianyy! I can't think in an exact reason why your tracker is showing gaps while you're sleeping. It could be that it's been worn incorrectly and low battery. However, I recommend restarting your tracker and check out with your physician just to make sure that everything is fine. I also invite you to take a look to this article.

I hope this helps. Let me know how it goes.

[Alnicole]

Same here, some random gaps during sleep and then a random 120 before back to normal stats...

[SunsetRunner]

@SunsetRunner  I can a similar reading at times...only not so often.  I have a tendency to sleep on the same arm that I wear the tracker.  Could it be that the blank time is when the fit bit was being compressed away from my wrist enough that fabric might have slipped in and interfered with the reading?

[Shbunk]

I too have this issue regularly, and have tachycardia. Recently (and scarily) there was a gap in my night recording followed by a spike of HR to 203bpm which came down slowly as it showed five mins later as 158 then just over 100 then in the 70's. Did we decide on a blip with the HR monitor or... 😳 I don't know wether to be worried or put it down to a blip with the device..

[USAF-Larry]

I see gaps occasionally when I'm sleeping, but haven't been too concerned about it. I assmed that it was because I was so still while sleeping that the tracker assumed I wasn't wearing it and turned off the sensors to measure HR.  My wife often accuses me of not sleeeping, but passing out! Ha!  That is because by the time my head hits the pillow, I am sound asleep.  I learned that in the military - when there was an opportunity to sleep, we slept! Ha!

[DaughterofMaat]

I have a similar problem, I get random gaps in my sleep at night, happens very rarely, but I don't get the spike to 120. It picks up right where it left off. And it lasts longer than 20 minutes, mine is typically for 30 minutes or 55 minutes. It's happened four times total since I got the Charge HR in February. I'm not sure why it happens, but like someone else said, it may just be that I was in such a deep sleep the Charge though I had taken it off and turned off the sensors temporarily!

But I love my Charge HR regardless and I'm reviewing it on my website this weekend because I'm so happy with it! 😄

[m00sah]

I have this issue every single night and it always seems to occur between 2 and 4 a.m.  There is only one night where I have had a continuous heart rate.  Since I am waking up in the morning, I take that as a reassuring sign *lol* My friend and I swapped our fitbits to see if it was just an issue with the fitbit itself but the gaps did not occur when she wore my fitbit, but did occur when I wore hers.  For the other fitbit users that are experiencing this, I am curious to know if any of you have ever been diagnosed with sleep apnea, a heart condition, seizures or thoracic outlet syndrome? 

[cece23]

I have this occasionally in the night, no heartbeat is registered for 10 or sometimes 20 minutes then it continues as normal - no spike. I do have sleep apnea, so that is why I am so concerned. I am going to trun my heartrate monitor to on as opposed to auto to see what difference that makes.

[Marrrmaduke]

The tracker probably moves down (twists away) your wrist and cannot pick up the HR.

[cece23]

No that is not it, I wear it fairly snug (I have a wide wrist) and its usually slightly moist under the watch (sorry for that visual) so it just plain sticks firmly in one place.

[Marrrmaduke]

@cece23 Slightly moist might be your problem. I remember months back when I used to sweat a lot during my workouts (sorry for that visual 😛 ), fitbit would lose my HR periodically. Actually it was quite often and the device was pretty snug too. I had to move it around and wipe under it, and boom there was my HR again. So perhaps try to loosen it up for the night. 🙂

[cece23]

That did cross my mind but when you think about it the whole point of a fitness tracker is to encourage people to get up, move around and get sweaty. It seems unlikely that sweat would interfere with the readings otherwise there would be a lot of complaints! And in any case I sweat loads more during the day when I'm sporting and get no issues whatsoever.

I'm concluding its probably what other people have been saying about being so still in the night the fitbit somehow is fooled into thinking you no longer wearing it. Though with my sleep apnea I do regularly stop breathing in the night I think if my heartbeat had actually stopped at any such point I wouldnt be alive to tell the tale 😉

[HelenaFitbit]

It's great to see you on the forums everyone! I'd like to provide some information about this. 

Your Charge HR is meant to sense your sleeping periods by using Autodetection. This is based on your movement and your heart rate. When you haven’t moved in over an hour and your heartrate is lowered, algorithms assume that sleep has begun, which is then confirmed by the length of time your movements only indicate sleep behavior (rolling over, etc). Morning movement tells your tracker that you’re awake. 

Whenever your tracker reports an awake period (even if you weren't) it means that you were moving around in bed such that the tracker has determined you weren't alseep. There is further info about this including changing the sleep tracking sensitivity setting in the sleep tracking FAQ help article. It's a good idea to also restart your tracker in case there is a temporary glitch.

Last but not least, please know that there are some cases where your sleep may not be accurately logged with an HR based tracker, this can be for different reasons, one of them a high resting heart rate or trying to rest after an intense workout, since it will take longer for your body to 'wind down' and recognize a sleeping pattern. 

Hope this helps! Let me know if you have any questions 

[cece23]

Nope that did not address the problem at all. It sounds like a generic answer and almost word for word what I have already read in the help. To be quite frank it sounds as if you have not really read and understood the problems people have been having. Its great wanting to help, but I am assuming most of the people here are fully capable, and probably have already, looked at the helpfiles themselves. When they can't find the solution they then turn to the forums for help.
To recap: the problem is that the heatbeat shows small gaps during some nights sleep. For some people the heatbeat then starts a few minutes later at the same heartrate it left off and for others it shows a sudden increase in heatrate when it commences, so we are possible looking at at least two different issues here. From what I understand this is not, for most people, a problem during the day. The problem has nothing to do with whether sleep was detected or the accuracy, it has to do with the fact the heartbeat is not detected at times.

[HelenaFitbit]

Thank you for your prompt response @cece23 as well as the clarification. 

Please know that I'd like to keep this thread friendly, polite and conversational; after all, we're all helping eachother out mmkay?  

Back to the response, we have some tips to get a better HR accuracy; these are mostly used for intense workouts, but they can certainly be used for a daily purpose. 

We do not have an exact number where we would consider a "minimum heart rate" number; as an example, this community member had the same problem; but had had a full medical test that determined a condition. So having a low resting heart rate can be caused for a different number of factors. However, the HR Accuracy tips work for everyone 

Let me know if you have any questions! 

[cece23]

I do not believe my response was unfriendly or impolite, I was merely saying that your response was not relevant to the entire thread. Just stating facts.
So I have read the first link you just posted just now. The factors mentioned seem more relevant to a person who is moving around. My fitbit is indeed snug but not tight as I wouldnt feel comfortable with that, so that is not the issue. I dont feel any of the other explanations are valid either as they would be just as likely to affect me during the day as at night and that is not the case.
With regards to second link, if I understand correctly what is being suggested by the community member is that below a certain heartrate the reading seems to cut out. My resting HR is always around 68 - 70 so I dont think a low reading is a factor but I do have sleep apnea where I stop breathing many times each night hence my concern. I have recently set my watch to on all the time instead of auto, but have not seen any anomolies yet.

[ciociosan]

I had a 35 minute gap in my heart rate chart last night during sleep.  It is highly unlikely my heart stopped beating for that long so other factors are at play.  

Most wearables with heart rate monitors today use a method called photoplethysmography (PPG) to measure heart rate. PPG is a technical term for shining light into the skin and measuring the amount of light that is scattered by blood flow. That’s an oversimplification, but PPG is based on the fact that light entering the body will scatter in a predictable manner as the blood flow dynamics change, such as with changes in blood pulse rates (heart rate) or with changes in blood volume (cardiac output).

The biggest technical hurdle in processing PPG signals is separating the biometric signal from the noise, especially motion noise. Unfortunately, when you shine light into a person’s skin only a small fraction of the light returns to the sensor, and of the total light collected, only ~1/1000th of it may actually indicate heart-pumped blood flow. The rest of the signals are simply scattered by other material, such as skin, muscle, tendons, etc.

The location of the wearable on the body presents unique challenges that vary significantly by location. It turns out that the wrist is one of the worst places for accurate PPG monitoring of heart rate because of the much higher optical noise created in that region (muscle, tendon, bone, etc.) and because of the high degree of variability in vascular structure and blood perfusion across the human populations.

I figure that, in my case, the light signals just got "scattered" out of range of collection for this particular algorithm, probably because of the band position on my arm.  And Helenafitbit gets the snotty award, not you.

[chargehrnewbie]

This happened to us too.

Moderator edit: Content.

[Silverbeat]

Have updated my original Fitbit (which worked perfectly) with a Charge2 and now have problems. It was fine for the first week. It is clean and dry, treated carefully and regularly charged.

The heart-rate graph has, most days, several gaps, usually, but not always, at night: as much as 30 minutes. I have also deleted the  App and reloaded it.  I use an iphone 5s. I have worn the tracker at different tensions and positions (as recommended) to no avail.

My latest problem is with the sleep function: my graph shows it  has suddenly decided that I am restless for most of the night and only sleep for 3-4 hours when in fact my real average, as shown previously, is just under 8.

Today it hasn't logged any heart rate graph at all for 5 hours.

It is only 1 month old. Should I send it back?