Fitbit Charge 4 Fitness Tracker Review: Twice as expensive as the Huawei Band 4 Pro and also twice as good?

Many manufacturers have been announcing blood oxygen measurements for a while now, but this feature has been slow to arrive in wearables. Fitbit built the sensor into the Charge 3, and so did Huawei in the Band 4 Pro. Both have recently enabled the feature with an update, and they also measure the heart rate around the clock. In training mode, Fitbit measures it once a second, otherwise every five seconds. 

Huawei includes two different sizes of silicon bands with the Band 4 Pro, and Fitbit also ensures a good fit with different wrist sizes by including two band sizes. The classic band, which was included with our test unit, is made from a harder plastic and slightly resists our attempts of putting it on. When wearing it, you do not notice the light band, just like with the Band 4 Pro. Subjectively, we prefer the material itself in the Huawei.

In the accessory program, additional sport bands in several colors, fabric bands made of polyester, and higher-quality leather bands from Horween are available for the Fitbit tracker. The case is made from plastic resin.

The selection of watch faces also suffers from the monochrome display. At the time of our testing, their number was limited to 24, while Huawei offers significantly more. However, Huawei's watch faces are all colorful throughout, and you can hardly find anything plainer.

Both trackers have a full touchscreen, which is not a given, as the simpler Band 4 from Huawei shows. Both also offer an additional button. In the Band 4 Pro this sits on the bottom edge of the display, and the Charge 4 has an inductive key on the left side. The cases of both are water resistant up to 5 ATM. The protection specified in the standard does not go much further than washing your hands, but both manufacturers still specify that you can also swim with their wearables.

You can then adjust the brightness (normal/dimmed/automatic), activate the do-not-disturb mode (DND), and make a few additional adjustments on the tracker. Using a swipe gesture from the watch face, you can access up to seven additional apps, such as the training app, calendar and weather info, as well as Spotify. In contrast to Fitbit smartwatches such as the Versa 2, there is no app store for the tracker. 

In the Charge 4, the key on the side consistently handles the "Back" function. So you always have to click several times to get back to the main screen from an app menu. In the Huawei, you get back one step by using a gesture, and the sensor key always takes you back to the main screen. 

The tracker signals incoming calls by vibrating. If you take the call, the call is run through the smartphone and headset in case you have connected one. If you reject the call, you can answer via SMS afterwards. Alternatively, the Charge 4 initiates the callback using the smartphone.

The health and fitness functions have always been extensive with Fitbit. The Fitbit app on the smartphone contributes a lot to keeping an eye on physical fitness and also nutrition and helps improve them. 

While other trackers often report steps and heart rates over the whole day and activities only for a manually started workout, the Fitbit analyzes activities and load constantly.  

With the Charge 4, Fitbit prominently introduces so-called "activity zone minutes." They also take the wearer's age, weight, and fitness into account, evaluating the daily activities differently. The Fitbit differentiates in three steps between fat burning, cardio, and high-performance zones. Examples are the effort made during a leisurely walk compared to a higher effort when walking quickly, or the high performance made while jogging. 

During the training, the Charge 4 signals changes between zones with a vibration: 1x for the fat-burning zone, 2x for the cardio zone, and 3x when reaching the high-performance zone.

However, in practice you don't need to pay much attention to the vibration to differentiate between the zones, and you can guess them by the feeling of your body anyway. Looking at the tracker proved to be little help, since you could hardly read the display in bright sunlight or while moving. While cycling, it was also difficult to see anything on the display in good weather, and the OLED really only looks bright on overcast days. With regular movement it is usually sufficient, and then it is also easier than while running or biking to turn the tracker on your wrist, so you can even read it in bright sunlight.  

What worked really well during the test was the automatic recognition of a training run. In our test, we confirmed the question "Track run?" on the display only after completing our run. But before then, the tracker had completely recorded the run, and then accepted it into the training list as an active workout together with the running route.