Fitbit Blaze review: can the best quantifier shine like a smartwatch?

If someone wants to buy a quantifier and asks for advice, Fitbit is surely one of the brands they suggest. In fact, they no longer only focus on quantifiers, but with Fitbit Surge and Fitbit Blaze, the company is trying to enter the popular world of smartwatches.

It is time to analyze the latest model, Blaze, a device that is not physically a wristwatch, but rather a quantifier module with a color touch screen that is assembled in a metal frame attached to a strap. In this modular way, it takes the form of a traditional wristwatch. How has our experience with him been? Is it an accurate device? Is it more a quantifier than a smartwatch?

Aesthetically it is a quantifier come to more

In the case of Fitbit Blaze, it is clear that design is not its strong point. We cannot affirm that it is a “dress” watch or that it appears to be. However, it can be among what we call a sports watch, for a gym, going for a run and having a few beers with friends.

It is not the best looking smartwatch on the market but it is a sporty and functional smartwatch


Fitbit Blaze


  • Touch screen
  • 16 colors 1.25 inch


Sensors and components

  • 3-axis accelerometer
  • Optical heart rate monitor
  • Altimeter
  • Ambient light sensor
  • Vibration motor


  • Monitors 7 days of detailed motion data, minute by minute
  • Monitor daily totals for the last 30 days
  • Stores heart rate data at one-second intervals during exercise monitoring and at five-second intervals the rest of the time


  • Radio receiver: Bluetooth 4.0
  • Range: 6 meters

Synchronizes automatically and wirelessly with computers and more than 200 of the main iOS, Android and Windows devices


  • Fitbit Blaze is sweat, rain and splash resistant


  • Up to 5 days
  • Type: lithium polymer
  • Charging time: one to two hours


  • 229.95 euros

Let's take a look at the module in question. We are facing a 1.25-inch, 16-color OLED touch screen, on the sides there are three buttons, one on the left side with the back function and two navigation on the right side. These buttons can be used once you insert the module into the bracelet.

The display is not always on, that is, it only comes on when you press a button or raise your hand to check the time. Unlike other smartwatches, this point is not configurable, it turns off yes or yes, there is no way to keep it on if you want.

As for the front of the module, it gives us the impression that the black frames of the module could have been used a little more, seen other smartwatches on the market. Of course, somehow they have to integrate a battery of sufficient size and capacity to give Blaze up to 5 days of autonomy.

Thickness is the most critical point of this design and much of the blame lies with the heart pulse sensor, inherited from the Charge HR, but this time somewhat larger - promising greater reliability in measurements.

However, it is true that the use of this metal frame notably conceals the thickness of the set making you not notice it more than any other smartwatch. The thickness seems to be hidden by the underside of the watch.

The support is made of brushed steel and the bracelets are fastened to it with a quick extraction system, something very fashionable, but one that many of us will use very occasionally.

Despite being of remarkable thickness, the Fitbit Blaze module + frame and strap assembly remains very tight once put on

What functions does Fitbit Blaze perform?

Here you can see the company's previous experience in the field of quantification. The Fitbit wearable integrates a series of very complete functions that, in addition, comes accompanied by an application that allows easy viewing in real time.

Blaze has a menu through which we navigate by sliding your finger on the screen or with the physical buttons, but we have already confirmed that it is more comfortable to use the screen.

These clock screens, covers or clock themes are active and as a user you can interact with them, the pop mode allows you to tap on the screen and numerically see the steps taken, beats per minute and calories expended. The zone mode changes the color background according to the number of keystrokes and the original mode allows you to change the lower numerical value to see any value that the smartwatch registers.

As a smartwatch, at first glance it is somewhat short since we only have those four topics to choose from (at the time of writing the review), leaving the Fitbit Blaze aesthetic very corsetted.

From that main clock screen we will have access to a menu to turn on or off notifications and access to the music playback controls or to the notifications as we slide from top to bottom or vice versa.

If we swipe from the bottom, notifications are shown. Although we can only do that. See the notifications that we configure from the application: Missed calls, SMS Hangouts or WhatsApps or calendar alerts.

Once we pass to the right we see the option Today, with statistics for the day, if we continue we get to Exercise, from where we can start an activity to choose between running, cycling, elliptical and other.

One of the added values ​​compared to the previous generation of products is FitStar, which is nothing more than a training plan assistant that recommends different routines to keep you in shape (warm-up, 7 minutes, 10 minutes of abs). It should be noted that the on-screen presentation is quite graphic and descriptive.

Fitbit is a large device, it will be difficult to fit well on small wrists

And finally, we have Alarms, timer and the missing option, Configuration, where we will have some basic adjustments to make to the clock - most also available from the mobile application.

In summary, the Fitbit Blaze has the following functions: tracking the steps we take, the calories we burn, the stairs you climb, the active time, heart rate and heart rate at rest and the time and quality of sleep.

In addition to this we have to comment that it offers a quite complete system for monitoring sports activities, being able to use the mobile's GPS to show the route we have followed and further specify the distance traveled.

As a device to be used as a silent alarm we have a somewhat ambiguous feeling. It is good that it warns you through vibration, on the wrist it is more than remarkable, but what does not seem optimal is that you can only configure them from the mobile.

Also, despite all the sleep monitoring and tracking it does not offer a smart alarm system, like other devices on the market that wake you up in a range of time during the lightest sleep phase.

Function analysis, precision and reliability

A lot of promised function, so let's go point by point seeing how Fitbit Blaze behaves in its different facets. Let us first analyze its quantifying function of steps and sleep.

For this we have taken into account a Misfit Shine and a Pebble Time as devices with which to compare the results. The precision of Fitbit Blaze when it comes to quantifying steps is outstanding, we know that Pebble Time is still in its infancy in this field. If we compare the precision against Shine we are in a difference range of less than 10 steps in a volume of 10,000 steps.

The quantification of steps is very precise, but not only that, the rise of plants (stairs) and hours of sleep are strengths of Fitbit Blaze

Sleep monitoring is quite accurate, even a night visit to the bathroom is recorded. It is not the device that offers the most data about sleep, but we can see periods of sleep, periods in which we are restless.

It is one step behind Jawbone that also estimates periods of deep and light sleep in addition to the REM phase. Conclusion: for more than enough basic measurement. If we compare it with Pebble Time, the total sleep time is very similar although with Blaze we have some more data and it is able to detect sleep breaks, night visits to the bathroom and compute the entire period as global sleep hours.

Now it is the turn of the exercise follow-up where Blaze offers different well differentiated profiles. We have: running, treadmill, bike, weights, elliptical and exercise in general. This is fine, but surely you agree with us that it is much easier if the device recognizes the exercise you do and automatically starts monitoring it. Fitbit Blaze does it.

Fitbit Blaze monitors your activity and automatically detects the type of exercise you do. Pleasantly surprised by their level of success

The Running or Bike mode make use of the mobile's GPS with which FitBit Blaze synchronizes to offer the distance traveled. They are the most complete tracking modes since it also monitors the pace or cadence of strides.

If you are going to run with the watch but without the mobile (ergo without the data obtained from the GPS of the same) the distance is not as accurate since it is estimated according to the number of steps you take and the standard measurement of a stride. In our tests, that estimate has turned out to be somewhat more positive than it should have been, I'll be a short-sleeper according to Fitbit.

Heart rate wrist measurement, quite reliable

In Blaze the cardiac pulse is measured continuously and apart from this it also ends up giving a number of beats per minute at rest. The most skilled athletes will be able to affirm that this type of measurement in the wrist is not precise, or - better said - not as much, as a chest strap, but this is the question.

It is true that when we run or do activities that involve a continuous movement of the arms, maintaining that measurement is more complicated to do and the reading is lost for a few seconds, but it is enough to follow some tips such as not wearing the bracelet too tight for everything to work as it should.

In the case of intense races, we recommend adding another element to the wrist, in the area closest to the hand. In this way we make sure to keep the 2-3 cm of margin that should be between FitBit Blaze and the wrist.

We have to strike a balance between comfort of use and precision. What is clear is that the data that Blaze offers is useful, and it will depend on the type of end user if that utility falls short or not.

At rest, during the day to day, the constant reading of the pulsations is quite accurate, not to say that it practically nails those of a chest tape, however the limitations are found when exercising.

Blaze recorded a few beats to the chest strap, usually in the range of about +/- 3 beats per minute from the baseline. It is a good enough precision to be an optical measurement system.

The problem comes when doing high-intensity work, beyond 155 beats per minute the measurements are somewhat erratic pulling low. If you are going to do training of this type, it is not recommended, especially if we take into account the small lag between the measurement and the result shown on the watch.

In addition to all the modes mentioned and although we have more to choose from the mobile, seeing that we are facing a waterproof device, we miss a swimming mode, which could be very interesting if it is as complete as the race or bicycle . However, in the box we only read Water Resistant, no IP68 protection or water Resistant 50m, so surely that is the reason for this absence and we should take it off even to shower as it is splash resistant and little else.

Heart rate measurement is accurate at daily or sport quantification levels up to a medium-high charge rate

Bottom Line: Heart rate measurement is fine for people who are just starting to do sports, gym or go for a run now and then. If you are looking to delve into sports, training in different areas of effort is difficult to bet on an optical measurement device, such as the Fitbit Blaze. For amateur sports use, it's fine.

Smartwatch with quantification functions? Rather the opposite

Blaze is a wearable that goes on the wrist and has a 1.25-inch color screen. In addition, the design of the same seems to push us to believe that we are dealing with a smartwatch but, the feeling after these weeks of testing is the opposite.

Our opinion: given the little flexibility of customization as a clock (only four predefined covers / themes) or the impossibility of setting an alarm directly from it, for example, it leaves us with the taste of being in front of a quantifier with some functionalities of smartwatch.

An example of the latter are notifications, covering messages, calls and calendar notices. Each of these sections can be customized, allowing, for example, in the messages section to choose WhatsApp. This option turns the Blaze into a notification screen, it would only be reading the received messages, not interacting with them.

In fact, the notification system is not that it works completely fine because, on some occasions, despite being connected and synchronized with the mobile, the notifications are not shown in Blaze. Without a doubt, this is Fitbit Blaze's weakest point.

The notification system transforms Blaze into a screen that shows calls, SMS or WhatsApp messages and calendar alerts, but forget about interacting with them.

Another of the functions promised by Fitbit is the control of multimedia playback and we have found that it is carried out using a traditional Bluetooth connection and not BT 4.0 LE. This implies that the user has to activate the classic Bluetooth mode on the watch and synchronize the Blaze with your smartphone again.

Fitbit app or how to effectively display all data

Fitbit continues to pull gallons in this field, proving that the app and device ecosystem is well-trodden. It makes use of the same Fitbit app as with its previous quantifiers, that is, with its gamification system, awards for achievements achieved and, in addition, visually attractive and easy to use.

Just like the previous point is, without a doubt, the weak point of the Fitbit Blaze device, the Fitbit app makes you win integers.

We can see not only today's statistics, but it is possible to filter by days, weeks or months, see the sleep averages or steps taken. But it goes further since you can even see a graph of the evolution of our beats per minute throughout the day.

It sounds easy, but simply displaying all of the quantified data is tricky. Fitbit has been polishing its application for years and it is something that shows. Not only for being a user-friendly application, but for its entire gamification ecosystem and the ease of reading data.

The ecosystem of functionalities and data visualization in the Fitbit mobile application is the other strong point of FitBit Blaze

Unlike the notifications theme, we have not had a sync problem at any time with Blaze. It offers a great mobile platform to visually display all the data it quantifies.

Autonomy: more than a smartwatch, less than a bracelet

Fitbit's promise is 5 days to live since you unplug it from its charger. In our tests we have been able to verify that Blaze fulfills what it promises. This fact is somewhat commendable given the autonomy that smartwatches offer, which we know does not go beyond a day or so.

It is true that we are facing fair notification functionalities, but even doing a couple of follow-ups of Blaze races has lasted as promised.

You will not have a week of autonomy in any case, but you can go outside for a long weekend and you will not have to take the charger, in a housing format where you have to lock the Blaze module and connect it to a port / charger USB.

The charge does not reach 2 hours and allows a use of up to 5 days

Taking into account its OLED screen and the constant pulse measurement, we found this autonomy remarkable. This is the result, in part, that the GPS data to monitor running or bicycle exercises is obtained from the mobile phone, which is the one who uses the battery for these purposes.

Fitbit Blaze, Xataka's opinion

After a two-week trial of Fitbit Blaze we are clear about several points. The design, while not the most beautiful, is functional. If you are used to wearing a quantifier bracelet, the weight difference is very small and you will hardly notice it.

If we have to put some but to the Blaze, we recover the ones described above: little customization on the clock part, somewhat random pulse quantification in high intensity training and a somewhat green notification system.

However, we have a long list of positive points: Fitbit app and the entire ecosystem around it, constant pulse measurement, automatic detection of the type of sports activity you do, its general precision and, finally, its autonomy.

As we have been seeing the sections we have wanted to guide you to see if Fitbit Blaze is for you. As a final recommendation, and in case someone has not yet decided, it seems to us an advanced quantizer with a screen of adequate size for data visualization. If you are looking for a balance that leans more towards the smartwatch balance, Fitbit Blaze may not be your device.

It has an official price of 229.95 euros in the official Fitbit store, in the line of other quantifiers and somewhat cheaper than Android Wear smartwatches. In fact it is a very tight price, we remember that the Fitbit Surge model has a price 20 euros more expensive.


Design7 Screen6.5 Software7 Autonomy9.5 Interface6.5

In favor

  • Autonomy
  • Wrist pulse measurement
  • Monitoring accuracy
  • Fitbit app and ecosystem


  • Design
  • Low resistance to water
  • Separate charger

Fitbit Blaze has been loaned for testing by Fitbit. Can inquire our policy of relationships with enterprises.

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