Fitbit Charge 4 on long-term test: Good features, but battery life with GPS is an issue

The Charge 4 performs very well as a general health and fitness tracker, but power users will want more granular metrics and a longer-lasting battery for GPS use.
Written by Sandra Vogel, Contributing Writer

Wristband wearables have come a long way, and these days we expect them to offer GPS, heart rate monitoring, alarms and a range of handset connectivity features. The £129.99/$149.99 Fitbit Charge 4 has all of these, plus a mix of other features, some of which Fitbit calls 'apps'. You can choose to show or not show these wristband apps, which include a contactless payment wallet called Fitbit Pay, on the device by making selections in the Fitbit smartphone app (iOS or Android). Pay £149.99/$169.95 for the Special Edition and you get a woven back wristband rather than a rubbery one. I've been using the Charge 4 for several weeks, and offer these observations as a follow-up to Matthew Miller's April review.


The Fitbit Charge 4 (£129.99/$149.99) offers heart-rate tracking, built-in GPS, goal-based exercise modes, water resistance, sleep monitoring, notifications and on-band apps.

Images: Fitbit

The standard wristband can be replaced with colourful or woven alternatives.

Image: Sandra Vogel / ZDNet

The overall design is familiar to anyone who has a previous Fitbit Charge device: an elongated touch screen; a single side (touch) button on the left edge of the Charge 4 (if worn on the right wrist); and a removable wristband that's easily replaced with colourful alternatives. The Charge 4 comes with two wristbands and I found the small one was fine for me. All but the largest of wrists should be accommodated.

The grey OLED touchscreen is large and you navigate around it using the side button and a mix of screen sweeps and taps. It's pretty easy to get used to how things work. Tapping on the clock face toggles through metrics like steps, distance, and heart rate. A range of faces can be set showing different selections of metrics, plus time and date, via the Fitbit smartphone app. Sweeping right to left brings up various wristband apps that have been enabled in the smartphone app.

Basic activity tracking works fine. You can tell the smartphone app your average stride lengths for both running and walking, and it shares this with the Charge 4, which can then convert paces into distance. It's not perfect, but I have always found Fitbit devices to be pretty accurate when tested on measured distances, and that remains the case with the Charge 4. 

The Charge 4 will automatically detect when you are running, cycling, on a treadmill or walking, and it is water resistant to the extent that you can swim for up to 50 metres wearing it without adverse effect. If you're serious about cross-training with these types of activities, then you might want a more sophisticated device that can deliver a greater range of metrics. But if you're just looking to do a certain number of steps or cover a certain distance, then the Fitbit 4 works well, including issuing alerts when you reach your preset goals each day.

With a heart rate monitor on-board, the Fitibit Charge 4 can do interesting things like measure your resting heart rate, set activity zones and report on these, and -- new for this model -- provide a report of Active Zone Minutes. This is a calculation based on age and resting heart rate, and the idea is to reach a goal of 150 minutes a week in your Active Zone. It's quite a clever idea for those using a Fitbit to burn calories or lose weight. Just ambling around is less helpful in this regard than moving a bit faster, and making your heart work a bit harder. As your resting heart rate lowers, the Fitbit changes its target minutes, so in theory there's always a relevant goal to aim at. Full reporting complete with graphs is available in the Fitbit smartphone app.

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Of all these metrics I found the resting heart rate information particularly useful. I have seen from previous Fitbit use how my heart rate fluctuates if I have a cold or fever, and how it falls as I get fitter, rising as my fitness wanes. These metrics can help people track their progress along a fitness trajectory.

The sleep tracking is also useful. I like to keep an eye on the hours I spend asleep, as well as monitoring my sleep quality to make sure I'm not short-changing myself. The Fitbit app has some nicely presented graphics showing overall sleep hours and periods of restlessness. If you really want to weigh in with the metrics, the Fitbit app gives you a sleep score based on the quality and duration of sleep, with a rating such as 'fair' or 'good' for each night. 

As for the additional features, I didn't bother with the Spotify controls, Fitbit Pay (a new feature with the Charge 4), the weather app, or notifications. My handset is the go-to place for this functionality, but I can see how some users may find them useful. What I like a lot is the silent, vibrating alarm, which is strong enough to wake me, but too subtle to wake someone else.


The Charge 4's charge cable is rather short, and fiddly to engage.

Image: Fitbit

The battery is rated to last for 7 days provided you aren't using GPS, in which case it's only good for 5 hours. This basically rendered the GPS unusable for me on long weekend walks, even if I started with it fully charged. That's a shame, as GPS is a big selling point for the Charge 4. I found the charge unit to be a bit of a fiddly fit, and I had to double-check that it was in place properly. Also, its cable is quite short, which meant my usual desktop charge station was just a little awkward to use. Long term this would likely be quite an issue.

Overall, the Fitbit Charge 4 has some excellent features and is a good step up from the Charge 3, while the Fitbit app displays a lot of quite complex information in an accessible way. Keen sports people will want a longer-lasting battery for GPS use and more granular metrics, but as a fitness tracker for general health the Charge 4 does very well.


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