Fitbit Charge 2 review: The Fitbit app, daily use, and verdict

Previously I unboxed the Fitbit Charge 2 wearable fitness tracker and gave a brief overview of its technology. Today I’ll talk about how it is to live with, and if it’s any good.

Wearing the Charge 2 is much like wearing a normal wristwatch. Its thickness, and how densely it’s concentrated, differs from how many of my wristwatches feel on the arm, though. Fitbit says not to do it up too tightly; as long as the PurePulse array on its underside keeps contact with your skin, it’s fine.

A full charge sees the Charge 2 last me about four days; a top-up takes under two hours.

Navigating through the device is done by pushing on the side button for going through menu pages, and tapping on the screen to go into options. This isn’t a true touch screen; instead there’s an accelerometer in the Charge 2 that detects finger taps. Because the device isn’t overloaded with functionality, this navigation method works just fine, although there are times when finger taps aren’t detected as well.

Much of the configuration of the Charge 2 happens on the Fitbit app for smartphones, which the device communicates with via wireless Bluetooth connection. You can configure the display of the watch face, as well as what metrics it tracks, what pages it displays, and what workouts you can launch from the Charge 2 itself. These include bike rides, walking, running, weights, and interval workouts.

Additionally, Fitbit brags that its “SmartTrack” technology has the Charge 2’s accelerometer and altimeter automatically begin tracking of any workout and classify it accordingly, as long as it lasts at least 15 minutes. Doing so has a few downsides, though, most notably that GPS tracking data won’t be included.

A bike ride captured via Fitbit.


Speed data from the ride.

Heart rate data from the ride. Note the heart rate zone analysis and breakdown. This ride incorporated a five-lap individual time trial around Daang Reyna, hence the 186 bpm peak.

This segues nicely into another capability of the Charge 2: “Connected GPS.” By itself, the device has no GPS; all it does is piggyback off the GPS radio of your phone. So if, for example, you decide you want to go on a bike ride, you can start it on the Charge 2, which will instruct the paired smartphone to begin location tracking via GPS. This can also trigger a new activity within a related app – in my case, this was Strava.

The same bike ride is also captured on Strava due to my setting up of Fitbit’s link-up to the popular cycling app.

Without a premium Strava subscription, looking into Segment Analysis is the best I could do to check my heart rate.

The upside of Connected GPS is that Strava will pick up the heart rate data the Charge 2 collects, and add it into the activity. You’ll need a Strava Premium subscription to make the most out of it. Alternatively, you can use the Fitbit app for analysis, since the info collection works both ways – Strava ride data will go into Fitbit.

Water intake tracking.

Food intake tracking vs. caloric expenditure.

Apart from activity data and its most basic function as a pedometer, the Fitbit app can also track your water intake and calorie intake from the food you eat. Yes, tracking food intake is tedious, especially when you have to create custom entries because its database doesn’t know a lot of foods that don’t come pre-packaged, but at least it’s no worse than the Samsung Health app I used to use for the job.

How good is the Fitbit Charge 2 at heart rate tracking and analysis? For most people, I think it will suffice. As I’ve previously mentioned, the PurePulse LED array may not be ultimately as accurate as a chest-mounted sensor strap, but it’s a tradeoff made in the name of convenience. That convenience means it can track your heart rate for a much longer period of time, and reveal any trends that might ring alarm bells.

While Fitbit calculated my functional threshold heart rate quite close to the 156 bpm I got doing Joe Friel’s method on TrainingPeaks, the heart rate zones themselves are a little rudimentary. It gives you essentially three zones – “fat burn,” “cardio,” and “peak” – which is some way short of the six usually prescribed by exercise physicians.

To Fitbit’s credit, they allow you to make a custom heart rate zone in addition to the ones they prescribe for you. I set this to 90%-105% of my functional threshold heart rate, to track the time I spend in “sweet spot” and “threshold” efforts. The downside to using the custom zone is that the Charge 2 vastly simplifies its live heart rate reading to display only the custom zone, and whether you’re in it or not. It’s a bit of a limitation, but one I eventually got used to.

Finally we come to the most unusual of Fitbit’s capabilities: it can supposedly track how well you sleep. Subscribing to the theory of multiple sleep stages, it can supposedly tell how much time you spend per stage by tracking your blood flow.

Honestly, this is a bit of a novelty to me, but I do have to credit Fitbit for getting it right with surprising frequency. At the very least, it validates that I’m a light sleeper at best – at least relative to most people.


Once you hit all your daily exercise/movement goals, the Fitbit app will acknowledge them by flooding the Dashboard screen with a green diagonal wipe.

Let’s get one thing straight: the Fitbit Charge 2 is not a smart watch. Apart from the Fitbit app, the only integration it has with your smartphone is that you can set it to notify you of calendar alerts, incoming calls, and incoming messages. For the latter, you are limited to only one messaging application – whether it’s the onboard SMS app, Facebook Messenger, WhatsApp, Viber, or something else. It’s fair to say that any smart watch functionality Fitbit gives you on the Charge 2 is rudimentary at best; given its limits, I find it does a decent job.

For everything else, the Charge 2 is surprisingly capable and put-together. Its screen is clear, it’s just about accurate enough to train with, and as long as you can stand the tedium of data input, the well-designed app does what you’d expect. It’s not cheap, you can’t swim with it, and there are real incidents of rashes and irritated wrists from the straps (easily remedied by keeping it dry), but for what it offers, I think it’s rather hard to beat. The only real downsides are the lack of actual GPS, the slightly simplistic heart rate zones, and lack of real water resistance.

First look: Fitbit Charge 2

After training indoors for more than a year, I have made notable strides in my fitness and ability. However, I’ve been pushing myself without an objective way of gauging how hard my efforts are.

The holy grail for cyclists’ training is a power meter. Coming in various form factors – from rear hubs, to road bike pedals, and single crank arms to entire cranksets – these tools measure the power output of a cyclist in watts in real time. The beauty of power meters is that for a given level of accuracy, power data is independent of external factors. Also, as a scientific measurement, watts can easily be translated into measuring the effects of other things such as aerodynamics and rolling resistance.

Alas, despite their prices coming down year after year, power meters are still expensive, and they don’t do anything on their own when not paired to a head unit – usually a Garmin, Lezyne, or Wahoo device that offers GPS navigation. These two components together can easily cost as much as a mid-range bike.

While power has nowadays overtaken heart rate as the premier training metric, athletes still use heart rate monitors as an instant measurement of their condition as they train. Lagging and fluctuations due to caffeine, stress, and emotional state aside, it’s still a valuable metric to keep track of; it was the best people had for a pretty long time. It also helps that, to some extent, many training concepts used with power can be replicated with heart rate.

With all that said, I decided to get a Fitbit Charge 2.

The Charge 2 is a wrist-worn fitness tracker which can be used to detect blood flow and heart rate via the green LEDs on its underside. As of this writing, it’s the most full-featured fitness tracker in the Fitbit lineup before moving into their full smartwatch offerings.

While ultimate accuracy of heart rate won’t be as great compared to pulse-sensing chest straps, the Charge 2’s more concise and more comfortable form factor means it can do its job for more of the time. Fitbit intend it for all-day use, where it claims to help track even your sleep patterns.

I bought mine from Tobys Sports for PhP8,490. Interestingly, they don’t stock it in any of their retail stores; you have to order it online. Based on wrist circumference, I got mine in the “L” size.

The only things of note included in the box are the safety instructions and the unique charger, which connects to a normal USB Type-A port and is essentially a giant clothespin that clamps onto the Charge 2. As it does, it mates to charging contacts on the Charge 2’s underside. Neat design, but also highly proprietary.

Finally, we have the Charge 2 itself.

A single sticker serves as a display mock-up as well as protection for the two green LEDs, heart rate/blood flow sensor array, and charging contacts on the underside. Via “photoplethysmography,” Fitbit’s “PurePulse” tech uses the green LEDs and light diodes to optically measure blood flow and pulse.

A couple other things about the Charge 2 are that it’s not waterproof, only splash-resistant; and that its wrist bands can be changed via the clasps on the underside. Unfortunately, this isn’t the device for you if you go swimming…but at least you can swap out the wrist bands if this included teal one is too loud for your taste.

In the next installment, I’ll delve into the Fitbit smartphone app and how the Charge 2 fares in day-to-day use.