This is my series of blogs on Garmin watches. Here are links my previous posts:
Garmin Forerunner 245 Music versus Forerunner 255:
Garmin Forerunner 245 Music, Forerunner 255, and Vivoactive 4 comparison: https://jimmy1photo.wixsite.com/blog/post/garmin-forerunner-vs-vivoactive
In this article, I will compare Garmin Vivoactive 4 versus Fitbit Charge 4. Firstly, I'm not happy with Fitbit Charge 4. That is one of reason I decided to get Garmin watch. So you might get a biased opinion on how Fitbit is a POS, which it is.
Walking Comparison
Walking is one of the easiest activity to track. I did a walk, and compared Vivoactive 4 to Fitbit Charge 4 directly. I'm right handed, so I typically wear watches on my left wrist. In the following comparison, Vivoactive 4 was on my left wrist, and Fitbit Charge 4 on my right wrist.
​ | Garmin Vivoactive 4 | Fitbit Charge 4 | Comment |
Time | 1:07 | 1:07 | No surprise here |
Distance | 3.50 miles | 3.22 miles | Garmin is more accurate, as Fitbit's GPS failed. |
Avg Pace | 19:16/mi | 20:36/mi | Garmin is more accurate |
Steps | 7,517 | 7,097 | Fitbit is more accurate |
Avg HR | 94 bpm | 109 bpm | Garmin is more accurate |
Max HR | 115 bpm | 135 bpm | Garmin is more accurate |
Calories | Resting 98 Active 290 Total 388 | 580 cals | I suspect Garmin is more accurate |
Intensity or Zone Minutes | 46 Intensity Minutes | 51 Zone Minutes | Garmin and Fitbit have their own definition and calculation |
Price (Typical) | $150 | $280 | Fitbit Charge 4 is cheaper than Garmin Vivoactive 4 |
Price (I Paid) | $70 | $170 | Fitbit Charge 4 is cheaper than Garmin Vivoactive 4 |
Time: Good to know that these smartwatches or fitness watches can measure time correct ;)
Distance: I cannot say whether Garmin is accurate or not, but I know Fitbit is not. Fitbit has major issue with GPS. And Fitbit GPS during this walk failed around 15 minutes into the walk. I will go thru Fitbit's Issue in next section below. But without GPS, there is no way Fitbit can measure distance correctly. I assume Fitbit is using the step count + assumption on stride length to estimate the distance.
Pace: Pace is Time divided by Distance. We know the time measurement on these watches is correct. So the variable is the Distance. Since Fitbit's distance is off, its Pace will also be off. So I know Garmin is more accurate than Fitbit.
Steps: I don't have true source of data for steps. What I did is count 200 steps; compared the data. I did this couple times, and got similar results both times. Fitbit is right on, and counted 201 steps. Garmin counted 210. So Garmin tend to overcount by around 5% (10 out of 200, or 5 out of 100).
And for the entire walk, Garmin counted 7517 steps; Fitbit 7097 steps. The overall difference here is 5.9%. This is not large, but kind of odd why Garmin cannot get the step count correct.
Heart Rate: During the walk, when Garmin read 95 bpm and Fitbit 110 bpm, I paused and measured my own pulse. Just run the stopwatch for 30 seconds and counted pulse manually. I got 96 bpm. This is very close to Garmin. Fitbit is way higher.
During the walk, Garmin ranges typically between 90 to 100 bpm, with average at 96 bpm. And I can also see the heart rate chart and trend on Garmin Connect app and website. In comparison, Fitbit was typically showing 105 to 115 bpm, with average at 109 bpm.
And as result, the max HR are also quite different, with Garmin reported 115 bpm as max HR, whereas Fitbit had 135 bpm.
Calories: Huge difference reported here by Garmin versus Fitbit. Although I cannot verify these #, I can speculate here. The devices uses Heart Rate + Body Weight to calculate the calories. Body Weight is same. And Fitbit HR is way higher than actual, as mentioned in last section. As result, Fitbit reported much higher calories spent.
Fitbit calculated 588 calories spent. I assume this is total calories, including both activity and rest. Garmin has breakdown of each: 98 resting + 290 active = 388 total calories. The difference is 50%, which is huge.
Intensity or Zone Minutes: Garmin reported 46 Active minutes, whereas Fitbit reported 51 Zone minutes. Surprisingly, these 2 numbers are quite close (only 10% difference), considering each company likely has different definitions. Unfortunately, these metrics and criteria are not well defined, so we cannot really dive into this calculation.
Garmin's Intensity Minute has Moderate and Vigorous. Moderate count as 1x and Vigorous has 2x multiplier. These are based on heart rate. But it is not clear exactly what heart rate ranges are needed to count as Moderate or Vigorous. Typically, I find that walking is roughly Moderate and running is Vigorous. In the example walk above, I walked for 1:07 minutes but only logged 46 Intensity minutes. So at the beginning of the walk, when my heart rate had not ramped up, it did not count as Intensity minutes. And toward the end, when I was a bit tired and slowed down, that also didn't count.
Fitbit has different terminology, but is very similar to Garmin. Fitbit calls this Zone Minutes. There are Fat burn zone (with 1x multiplier) and Cardio and peak zones (with 2x multiplier). Similar to Garmin, Fitbit does not exactly define what counts as Fat burn versus Cardio and peak zones. In my walking example, Fitbit Zone minute was also shorter than my actual walk; just like Garmin. Fitbit's Zone minutes is higher than Garmin's Intensity, either because Fitbit incorrectly measured higher Heart Rate and/or because HR zone ranges differ.
Issue with Fitbit Charge 4
I bought Fitbit Charge 4 to track exercise. And although does a decent job on that, there are major issues regarding GPS, interface, and usability. Overall, Charge 4 is a POS device. I think I got it on sale for $100. Yeah, I got what I paid for. Even at $100, it was overpriced as a glorified step counter.
GPS: Charge 4 uses the connected Phone's GPS when available. And if that is not available, it will use built-in GPS. Typically, around 10 minutes into the activity, the GPS will likely fail. So the entire activity does not have GPS or map data. If I take a 15 minute walk, it is 50/50 if I will get GPS data. If I go for longer walk, like 30 minutes or longer, the GPS will fail and there will be no map data. GPS function is completely useless.
Interface issues: Both touchscreen and gesture do not work well. When display is off, I need to touch the screen 5-10 times to get the device to register and turn on the display. Yes, it is that bad. Alternatively, the gesture (raise to wake) does not work well either. It might work 1/3 of the time. When it does work, device is very slow and has 1-2 seconds lag.
The work around is to use physical side button to wake up the device. Once the device is awake and the display is on, the touchscreen works ok. This issue is not just on my unit. If I duckduckgo, there are many reports of this issue.
Screen: Unreadable outdoors in bright sunny day or cloudy day. There is just not enough contrast or brightness. In addition, the display is below the top cover glass by several millimeters (or fraction of inch). This adds internal reflection and glare. Basically have to cover or shade the watch with other hand to even make the display slightly readable.
Comfort: Two issues here: form factor design and band. On the design, the part of the watch bottom that sticks out and form contact with the wrist is 1/2" by 1/4". That is it. And in this small area has 4 optical sensors plus the charging ports. This small area is pressed into the skin, including the charging ports.
The band feels like hard plastic, instead of soft silicone used by Apple Watch or Garmin. The result is that Fitbit is extremely uncomfortable to use.
Conclusion
Garmin Vivoactive 4 is a more accurate fitness watch than Fitbit Charge 4. Vivoactive 4 has better GPS, which results in usable distance measurement and pace calculation. Vivoactive 4 also has more accurate Heart Rate data, which affects Calories and Intensity/Zone Minutes calculations. Charge 4 does have more accurate step count than Vivoactive 4.