After trying something new with the Blaze pseudo-smartwatch, Fitbit's most recent endeavor is an upgrade to one of its most popular devices. The Charge 2 has already booted the Charge HR from Fitbit's website, and rightly so since it's essentially a refined version of the original tracker. Launched with the new style-conscious Flex 2, the $150 Charge 2 lies smack in the middle of Fitbit's family in terms of price and features. It does everything the Charge HR did, with a larger display and new swappable band options, and it can now also track estimated VO2 max and guide you through interval training exercises. But are those new features enough to persuade current Charge HR users to upgrade? Should new users give Fitbit a try with this device?

Design: Familiar, with more choices

With its 1.5-inch OLED display and attached band, the Charge 2 looks much like a stretched-out Fitbit Alta. Unlike the Charge HR, the Charge 2 has interchangeable bands so you can detach both sides of the band from the center module and replace them with differently colored and textured options. While it doesn't have the ostentatious jewelry options that the Flex 2 has, you can get the Charge 2 in black, purple, blue, and teal, as well as two "special edition" options, one with rose gold accents on the module and a lavender band and one with black module accents and a black textured band. If you're feeling fancy, you can also get leather bands in pink, brown, and blue colorways for the device.

Specs compared: Fitbit Charge 2 vs other Fitbits Device Charge 2 Charge HR Flex 2 Blaze Surge Price $150 $130 $100 $200 $250 Display type 1.5-inch OLED narrow OLED 1-inch OLED, flashing lights-based color LCD touchscreen 0.82 x 0.96-inch monochrome LCD GPS connected GPS none none connected GPS onboard GPS Heart rate monitor Yes Yes No Yes Yes SmartTrack auto-tracking Yes Yes Yes Yes Yes Smart notifications Call, text, calendar Call Call, text Call, text, calendar Call, text Estimated VO2 max, guided breathing Yes No No No No Interchangeable bands Yes No Yes Yes No Battery life 5 days 5 days 5 days 5 days 7 days

The Charge 2's design is familiar, which will make it a seamless upgrade item for anyone who has an old Charge HR. Interchangeable band options are how Fitbit is hoping to infuse excitement into the design, but the bands are ultimately the same types we've seen on nearly every Fitbit device. The Flex 2 has more versatility with its smaller construction and a plethora of bangles, necklaces, and wristbands to choose from. But even then, all of the new options are still pretty predictable. Another important difference is that the Flex 2 is Fitbit's first swim-proof tracker—the Charge 2 is only splash-proof, so don't try to go into the pool with it.

Aside from the larger display, the Charge 2 doesn't differ too much from the Charge HR aesthetically. It doesn't even have an onboard GPS, which would be a big differentiator, but it can connect to your smartphone's GPS to map outdoor activity. Its underbelly has an optical heart rate monitor that measures your pulse throughout the day, contributing to your heart rate readings, "cardio fitness level" score (or estimated VO2 max), and guided breathing exercises. Also on its underside are two charging nodes to which the proprietary charger connects when you need to get more power. The Charge 2 is supposed to last up to five days on a single charge, and I found that estimate to be accurate.

Like most of the other Fitbit devices I've used, the Charge 2 is easy to wear and doesn't become uncomfortable during long workouts. Fitbit has had issues in the past with Fitbit Force users developing rashes and skin irritations, enough to have the company recall that product a few years ago. It's important to remember that only the Fitbit Flex 2 is waterproof enough to withstand swimming, so I avoided getting my Charge 2 wet and wore it snuggly around my wrist, but not so tight that it would cut off circulation. You won't be able to avoid sweating on the band if you work out regularly, so taking it off for a few minutes a day (likely when you're bathing) should keep any skin irritation at bay.

Valentina Palladino

Valentina Palladino

Valentina Palladino

Valentina Palladino

Valentina Palladino

Not as many new features as you may think

Fitbit's Charge 2 and Flex 2 are not radically new and different gadgets; they are examples of fine-tuned devices that build on the success of older models. The new things you can do on the Charge 2 are monitor your "cardio fitness level," or estimated VO2 max measurement, and set up interval training. VO2 max is the maximum rate that your body can use oxygen during intense exercise, and the most accurate way to measure it is to be hooked up to multiple machines that measure heart rate as well as oxygen and carbon dioxide output and input.

The Charge 2 is certainly the cheapest fitness tracker that can give you an estimate of this statistic (a few high-end Garmin and Polar devices measure it as well), but Fitbit translates it into a "cardio fitness" score that places you on a spectrum for people of your sex and age. The Charge 2 measures VO2 max over time by taking into account your profile, heart rate, and workout data, so your score will likely change by a few points as it gathers more heart rate and workout information. While it's a useful metric that can tell you how fit you are overall and can give you a glimpse into how efficiently your body uses oxygen during a workout, the cardio fitness score should be taken with a grain of salt. The Charge 2's heart rate monitor was fairly accurate in my testing, but since VO2 max also requires an oxygen measurement to be truly accurate, cardio fitness scores are truly estimates and nothing more. Also, if you're just using the Charge 2 to track daily movement rather than hardcore workouts, you probably won't look at that score often.

The new interval training feature is basically a customizable workout option that combines short periods of rapid movement with short rest periods. In the Fitbit app, you can set how long you want to move vigorously and how long you want to rest, and the band will vibrate at the end of each interval, signaling you to change. I tried the feature out on my gym's ARC trainer, going full speed for one minute then resting (or in my case, slowing to bring my heart rate down) for another minute. I've done this routine many times before while using the timer on the machine to track my intervals, but the Charge 2's interval training feature made it much easier. I simply waited to feel the vibration on my wrist instead of constantly having to look at the machine.

The rest of the Charge 2 experience is similar to that of the Charge HR or the Alta. The new device tracks daily activity, steps, and its included workout routines, as well as sleep and continuous heart rate. The device's display shows you the time as well as steps, heart rate, distance, calories, floors climbed, and active minutes when you tap on it. Pressing the singular side button scrolls between the home screen, live heart rate readings, workouts, a stopwatch, and the new Relax feature that guides you through slow, two-minute breathing exercises. The inclusion of Relax will be a perk for anyone serious about meditating or taking a moment during the day to clear their head. As someone whose heart rate can speed up from frequent bouts of nervousness, I found that Relax helped me calm down throughout the day.

The Charge 2's larger touchscreen lets you interact with the device more than you could with the narrow display on the Charge HR, and one of the best things you can access is the workout shortcuts page. You can save up to seven workout profiles to start tracking a session quickly without using the mobile app. SmartTrack, Fitbit's automatic activity recognition system, only works for a few exercises—including running, walking, and biking—so if you frequently use the elliptical, do interval training, or engage in another exercise, the shortcut will become your best friend. You only have to press and hold the side button when your chosen workout is on the screen to begin tracking. The same gesture will stop the monitoring when you're finished.

Fitbit's auto-tracking continues to impress, though, so you can rely on that feature to pick up most running, walking, and biking workouts (it can also auto-track "aerobic workouts" like dance and Zumba, as well as a few select sports including basketball and soccer). I'm not a seasoned runner, so I often alternate running a few minutes with walking a few minutes, and I was worried that the Charge 2 might not record my workout because of that back-and-forth. Not so—it registered just about 30 minutes of running (which was more like 20 minutes of running and 10 minutes of power-walking) without me starting a workout manually. The graphs in the app reflected my heart rate as well, showing where I peaked during the hardest parts of my run and where my heart rate gradually slowed down when I transitioned to walking.

Other Fitbit devices have had smartphone notifications for some time, and the Charge 2 can similarly receive call, text, and calendar alerts. The screen isn't large enough to let you read full text messages, but the first few characters will appear along with the sender's name (if they are a contact) or number. The Blaze is Fitbit's true smartwatch, so all of its other devices are going to feel limited in comparison, but those short alerts do help if your smartphone is across the room and you want a peek at who's contacting you. But the notifications also feel a bit limited when compared to Garmin's $150 Vivosmart HR, which can receive all of your smartphone's alerts.

Fitbit has also incorporated little messages it calls "Chatter" that will buzz your device and appear on the screen every now and then. They're mostly motivational, encouraging you to move or be active, saying things like "Go for 150 [steps] more!" You can turn off Chatter if you'd rather not have them blowing up your wrist, and those messages are separate from reminders to move, which you can set for certain days and times of the week or turn off altogether.

Listing image by Valentina Palladino