Fitbit Charge 4 review

How I got my Charge 4

I never was into sports or fitness, but I am always into data and analytics. I got my first fitness tracker out of curiosity to just track steps. It was some cheap Mi band for ~$20. It did a primary job – counted steps, tracked sleep. But then Fitbit released Charge HR with 24/7 heart rate tracking and since then I’ve been using Fitbits.

First Charge HR stopped working after ~2+ years (two main problems: band began to crack (it was not replaceable) and some screen problems, still it tracked and sync just fine. Warranty was ended so I decided to upgrade to Fitbit Charge 2.

It was mostly excellent. But due to daily usage screen has cracked. And in late 2019, I also started exercise more heavily and noticed it’s the most significant flaw – heart rate tracking under higher intensities just panicked and stopped working altogether. During exercise HR started gradually going up, it went until max 130 and then broke down – began showing 70, or just “–“, which was very annoying giving, that I love tracking my HR.

So in early 2020, I began looking for something new. First I bought another cheap Mi Band 4, but it was not good. It did the basic stuff, but statistics were somewhat limited. So I gave Mi Band to my wife. Then I bought Galaxy Watch Active 2 (I’m Android user, so can’t go for Apple Watch), thinking that it will be a step up after Fitbits. Watch Active 2 was perceived by many as the best Android smartwatch. I returned it after one week. Heart rate tracking is garbage – inaccurate and hard to understand. And worst of all – it didn’t show Office 365 notifications from work (Email, Teams etc.). Bummer… So my eyes looked back into Fitbits. Versa or Ionic are too big for my taste. And Charge 3 was already dated (2 years since release). But there were no rumours about any new Fitbits. My Charge 2 was still working, so I decided to wait. And then one April day – Voilà- Charge 4 is released. So I instantly ordered one.

Charge 4 review

Because it’s my 3rd Fitbit device and because I can compare it to other devices I have used (Mi Bands, Galaxy Watch) I thought – why not to review it? So let’s try—my first gadget review.

Design and Built quality

Design and build quality is familiar to the ones who had Charge 2 or Charge 3 – it ain’t much different. So, in short, it’s great. You can also use Charge 3 bands. The screen is excellent as well. UI is intuitive, but Charge 2 was more straightforward. It has many screen faces, but I like plain and simple: date, time, steps, HR.

With Charge 4 (same as with Charge 2) I have two complaints about build:

  • Screen needs much better protection. It’s effortless to scratch and break glass wearing it 24/7. So this time I instantly put screen protector – maybe it will protect for a bit longer.
  • Band quality and impact on the skin. In general, it’s quite good – comfortable and durable, but wearing it for a month non-stop – skin starts to dislike it and starts showing wearing signs – some red marks and itching. Usually, what I do – I replace hands from time to time, and I try to find a real leather band, which is better for my skin.


Fitbit Charge 4 tracks many things: Steps, Floors, 24/7 heart rate; resting heart rate; Sleep stages; Oxygen variation in blood during sleep; Detects different sports activities. And most of these things, Charge 4 does excellent.

But most of these features were already in Charge 2… There are two main differences in tracking capabilities: Charge 2 didn’t track oxygen variation and Charge 4 tracks heart rate more accurately during higher intensities.

Let’s did deeper into tracking categories.

Heart rate tracking

I like how Fitbit handles hear rate (HR) tracking. It tracks HR 24/7 and nicely visualises HR with charts. I also really love the resting heart rate (RHR) metric, which really can show a lifestyle impact on heart and overall health. On the left chart, you can see 7 healthy days in the row (no alcohol, smoking, healthy diet and exercise) and how they affect RHR: from 70 to 55. On Right chart, HR peak shows exercise. HR tracking is one of the main Fitbit selling points for me. Mi Bands and Galaxy Watch Active 2 are way behind with HR tracking.

Sleep tracking

Sleep tracking is another powerful Fitbit feature. It does it well and again – app and visualisations are fantastic. Fitbit accurately detects bed and wake up times and sleep stages. Sometimes I don’t understand how these sleep stages affect sleep quality, e.g. many times awake at night might indicate lousy sleep, but sometimes I feel, that I had a fantastic sleep, or vice-versa. Still, in most cases, the indication is quite accurate. Fitbit also gives you sleep-score, which is made of a) sleep time; b) restless (awake time); c) resting heart rate and time in different sleep stages. I can’t say that scores provide any value to me as it is rather stable at ~80-85. I know, that in Fitbit premium you get more details and score brake down (tested trial), but I think it’s not worth $9.99 per month…

New feature to me – oxygen variation tracking. That was already added to Charge 3, but it was missing my Charge 2. It shows just chart and norms, so it’s a bit hard to make any meaningful conclusions out of this metric. I had one or two nights where norms where exceeded, but “so what?” Should I worry? I think Fitbit need to make this metric more transparent and user friendly.

Fitness tracking

I am not a very sports person. I do exercise regularly, but mostly I do indoor weight/body-weight exercise or walking, hiking. I also developed the habit before starting exercise to click on my Charge 4, that I am in “workout” mode, so Fitbit doesn’t need to guess. Usually, it detects other activities excellent as well – e.g. outdoor bike, walking. (PS. I don’t run). Sometimes it misinterprets… Last weekend it logged “Outdoor bike”, while I was cutting my lawn.

Charge 4 also has GPS. I tested it during a couple of walks – it works but drains the battery fast. 1-hour walk and battery from full went to ~15%. My outdoor activities usually include walking, biking and hiking. In all cases I carry a phone with me, so rather Fitbit would use my phone battery for this instead of own. But for now, it can’t. This feature “coming soon”… Let’s hope really soon.

Another selling feature of Fitbit Charge 4 – “Zone Minutes”. The idea is simple: when HR is in Fat burn zone (~110-130 BPM), you earn 1pt per minute, and when you in cardio or above (130+ BPM) you make 2 pts. per minute. These points add-up to “Zone minutes”. The idea is good, but the realisation is imperfect. For now, I would prefer simple “Active minutes”… The problem is, that for counting Zone minutes Fitbit only uses HR data and no other data. So when I’m chilling with beer and cigarettes – my HR is high and Fitbit gives me cheer-up for earning 22 zone minutes! Nonsense… It should count only active minutes as it was in Charge 2 and then only multiply some of them when you are in higher cardio zones.

This day as was mostly partying and didn’t exercise, but Fitbit counted 60 “zone minutes”. This should be fixed!

Smart features

Fitbit also has some nice smart features. Notifications are great, and I also receive my Office 365 notifications (not like Galaxy Watch Active 2). It also has NFC for payments – but PIN entry is not convenient, and I’m fine paying with my card, so until I can’t pay with my fingerprint – I don’t care about payments by tapping the phone, watch or boot. I love alarm; Fitbit promises, that I will be “Smart alarm” based on sleep stages. Fitbit says it’s coming soon, but we know how soon oxygen variation came to Charge 3… Another excellent add-on to Fitbit Charge 4 – Spotify control. It’s not perfect as You can’t change songs while exercising, but I enjoyed controlling my Bluetooth speaker without a phone while at home.


In short, I am satisfied with the purchase. It does a great job providing some statistics about life: sleep, HR, activity level; also it serves as a very basic smartwatch with time, alarm, notifications, music control, weather, timer etc. It’s all that I would expect from a great activity tracker.

It’s not perfect though… Fitbit should:

  • Improve “Zone minutes” algorithm, to count only “really” active minutes and not just an elevated heart rate.
  • Release “coming soon” features (assisted GPS from phone and smart alarm) ASAP and next time release Fitbit without “coming soon features”. Fitbit, you are a big company, you can do it faster!
  • Next Fitbit should have some Gorilla glass for protection.
  • Should improve oxygen variation to make it more user friendly and usable for some conclusions.
  • It’s a pity that Fitbit holds some sleep tracking features under “Premium”. I have 3rd Fitbit device so I might call myself “loyal” customer, but paying monthly $9.99/m is way too much.

Besides these few minors issues, Fitbit Charge 4 is an excellent product. But… If you don’t care about GPS, I would recommend going for Charge 3, which you can get rather cheap now. Other features like Zone Minutes, Spotify control and Fitbit Pay are rather gimmicks at least for now. But of course, if you are one of those few who like tapping watch to POS terminal instead of credit card, then it’s definitely for you.





One response to “Fitbit Charge 4 review”

  1. Pulse Avatar

    Awesome review, it’s been hard for me to get the charge 4.

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