Skip to content
Fitbit charge technology

Fitbits heartcentric fitness band falls short of perfection

Share Facebook Twitter Whatsapp Email

The Good The Fitbit Charge HR adds continuous heart-rate tracking to all of the other features already available in the stepdown Fitbit Charge for just a bit more money. Resting heart-rate readings reasonably accurate.

The Bad Design and fit aren't ideal for glancing at heart rate; active exercise causes accuracy drop-offs; not shower or swim-friendly. OLED display turns off after a few seconds, which gets annoying. Heart-rate coaching and goal-setting isn't intuitive.

The Bottom Line Fitbit's Charge HR adds heart-rate tracking to an already solid fitness band at a great price, but all the kinks don't feel fully ironed out yet.

I think back to when fitness wearables first emerged -- devices like the Fitbit -- and wonder, what made them so great? Why did people get so excited?

Was it really the fitness, or was it the idea of turning fitness-based into something fun?

That's an important point to consider, I think, and one that's being lost a bit in the latest round of fitness trackers. Fitbit, like other connected pedometers, counted steps. But it also made a game of it: hit a goal, get a reward. Share your progress with friends, and compete. Gamification, a catchphrase a few years ago, is exactly what these FuelBands, Jawbone Ups and Fitbits provided: they're carrots on a stick to motivate exercise.

The Fitbit Charge HR is Fitbit's latest big fitness move: it adds heart-rate tracking, something tons of bands and trackers have started adopting. It tracks heart rate 24 hours a day, even when you sleep. It syncs everything to your phone. It still looks like the older Fitbit bands, but it does more.

Fitbit Charge  
(Sarah Tew/ CNET)

For $20 more than the non-heart-rate-tracking Fitbit Charge, this seems like a no-brainer ($150 versus $130 for the Charge in the US; in the UK, it's £120 versus £100, or $180 versus $150 in Australia). And it is, mostly, in theory. The more expensive $250 Fitbit Surge does practically the same things, but adds a larger watch display and can track runs via standalone GPS. $150 for the Fitbit Charge HR is a good price for a full-featured device.

And yet, in practice, something about the Charge HR feels a step short of exciting. It's how Fitbit handles heart rate. It's how it feels to wear. And, it's how useful -- or not -- I found the addition of heart rate to be in my daily routine. It's one of the best wrist-worn heart-rate trackers out there, but it's not the complete slam-dunk fitness band I expected it to be. It is, however, the best Fitbit band currently available.

I'd just think twice about whether Fitbit's latest is the best fit for you. 

Fitbit Charge
(Sarah Tew/ CNET)

Design: Welcome back, old Fitbit 

The Charge HR looks nearly identical to the Fitbit Charge, and to the discontinued Fitbit Force before it. It has an innocuous rubberized wraparound band, with a narrow black OLED display that tells time, steps, and other data. You need to press the side button, however, to see anything on the display.

The rest of the Charge HR is actually somewhat changed. The strap now attaches with a standard watch buckle-type clasp, making it more secure and less likely to pop off. And the underside feels different, too. An optical heart-rate monitor with green LEDs bulges out of the bottom, pressing against the skin a bit when the Charge HR's properly secured.

Fitbit charge

(Sarah Tew/ CNET)

My skin got used to it, but the Charge HR definitely feels less comfortable than older Fitbit bands. Also, you have to wear it differently: Fitbit recommends wearing the Charge HR a finger's length above the wristbone on your arm for ideal heart-rate readings, which is farther up my own arm than I prefer to wear things. It's prone to disappearing under a long-sleeved shirt cuff.

The Charge HR comes in several muted colors; my review unit was black. It comes in several sizes, too, although each can be adjusted significantly. My large model felt OK on me, but the further-up-the-arm fit ends up feeling awkward over time. Maybe that's why a new watchstrap-style buckle is on this version: it helps keep the Charge HR clinging further up my arm...sort of.

The Charge HR comes with its own USB dongle for charging, but while it attaches the same way as older Fitbits -- straight out from the bottom -- it annoyingly uses yet another proprietary connection. That's right: a new dongle. Don't lose this one, either. 

Fitbit charge
(Sarah Tew/ CNET)

Heart rate: All day on your wrist 

Once attached, the Charge HR immediately flashes its green LEDs to gather heart-rate data. It does it all the time. That, plus a built-in accelerometer and barometer gather data on steps, heart rate, elevation (steps climbed) and intensity of exercise (walking, or running).

Fitbit's heart-rate technology is called Pure Pulse, and exists on both the Charge HR and the step-up Surge fitness watch. It works automatically, from the moment it goes on your wrist. The Fitbit Charge HR found my heart rate quickly and held onto the reading, so I could access it quickly by pressing the side button and cycling through to heart-rate mode. Compared with the Basis Peak, another green-LED optical wrist band with all-day readings, it offered similar resting heart rate readings. When I got more active, however, the reading fluctuated, sometimes jumping up or down, much like many other optical fitness bands do. The Charge HR did seem to capture and retain my heart rate better than many other recent wrist bands I've tried.

The Fitbit Charge HR can also track individual exercise sessions by holding down the side button. This starts a separate timed event with its own heart rate recording, which gets synced with the Fitbit app as its own discrete activity. It also tracks average and peak heart rate in that session.

If you've used a Fitbit before, the step and exercise elements work exactly the same as before. The heart-rate aspect, however, is new...and a bit confusing to interpret. 

Fitbit Charge

Fitbit's heart-rate charts. (Screenshot by Scott Stein/ CNET)

Yes, the Fitbit Charge HR gathers heart-rate data, and does it consistently. But what it does with that data, and how it helps you, becomes a bit fuzzy. The app presents charts of every day's fluctuating heart rate, and counts the minutes spent in higher heart-rate target zones, which it calculates as exercise. The problem is, higher heart rate doesn't always mean active exercise. Sometimes, my own heart rate drifted into a "fat burn" mode, but I knew it was more likely due to having had too much coffee.

The Charge HR calculates heart rate "burn zones" based on a formula of 220 minus your age included in the Fitbit profile, but you can customize your own as well in the app. Zones are color-coded as yellow, orange or red (fat-burning, cardio and peak), and on the Charge HR you can see your heart icon in one of three positions to indicate whether you're currently in that zone.

I should get a certain amount of cardio a week, or so my cardiologist says, but the Charge HR doesn't make it all that easy for me to target and achieve those goals. I didn't even know what the "burn zone" data meant until I dug up the information under Heart Rate in settings, and even the pop-up icon on the OLED display isn't all that intuitive.

The design of the Charge HR isn't conducive to frequent heart-rate checking, either. You have to keep tapping the Fitbit (a double-tap can be customized to bring up time, step count, heart rate, or another reading), or pressing the side button. Most of the time, the Fitbit Charge HR just isn't easily glanceable: the screen is dark, usually. That's where the always-on screen of the more expensive Fitbit Surge could come in handy, but there are other options out there too with more watch-like LCD displays, like the Basis Peak.

The Charge HR also calculates average resting heart rate, mainly from your sleep time. Mine was in the high 60s: not great, but I can work on it. Sleep tracking happens automatically, too, but I found it less detailed and accurate than what other basic sleep tracker-watches like the Withings Activite Pop could provide...which is odd, because heart-rate-enabled all-day trackers like the Basis Peak and Microsoft Band use heart-rate data to improve sleep-tracking info, while this Fitbit doesn't seem to take advantage of that data. The Charge HR generally showed I was sleeping far more restfully and with fewer interruptions than what the accelerometer-based Withings Activite Pop told me (I was actually sleeping restlessly with a cold). 

fitbit charge
(Sarah Tew/ CNET)

Accuracy quirks 

During my week or so with the Fitbit Charge HR, all wasn't dandy. I found the step counting and estimated calorie burn to both run higher and more generously than on other wearables I've used. I hit 10,000 steps a lot faster than when using a Withings Activite. I trust the Activite's readings more: they also matched what my phone's pedometer estimated.

My review unit also had some sort of barometer error: it said I've climbed over 1,000 flights of stairs in a week, when I've probably climbed closer to 20. I haven't heard of others having this problem, but it's concerning.

Heart rate accuracy was decent enough when resting, but during active exercise the readings tended to go a little more off-course. It was hard to tell when I was in a peak workout zone, a problem I've seen in other wrist-worn readers. The Fitbit Charge HR isn't medically approved for heart rate, and neither are any other heart rate-reading wristbands. To doctors, these are recreational devices. Take heed in case you're looking for medical accuracy.

During active exercise, I found the Charge HR to drop off in accuracy. I wore a Basis Peak on one wrist, the Fitbit Charge HR on the other, and a Polar chest-strap heart-rate monitor for the baseline most accurate heart rate. Then I went outside and briskly jog-walked for a while.

The Fitbit Charge HR was up to 20bpm lower in its reading than what the chest strap reading gave me. However, it was a lot better than the Basis Peak during active exercise. Once I rested for a few moments, the readings caught up and normalized quickly. When resting, the Charge HR gave very close readings to the chest strap. So, it's better than I thought it would be, but if you're a serious runner who's looking for a way to track heart rate during exercise, I'd absolutely go with a chest band (from Polar or Garmin, for instance) instead. 

fitbit charge

(Sarah Tew/ CNET)

Varying smarts 

The Fitbit Charge HR can show incoming call notifications, like the Fitbit Charge. It's useful in case someone's calling while you're at the gym, but the Fitbit's buzz is so quick that I missed it a few times.

Notifications require you to turn on an extra pairing setting in the Fitbit app, that allows for notifications and continuous syncing. I found Bluetooth pairing on an iPhone 6 Plus to be a mixed bag: sometimes I found the app spinning its wheels trying to establish a connection. Once it paired, all was fine. But it's not exactly intuitive to troubleshoot.

The Charge HR can also automatically track sleep, a feature in other recent Fitbits, too. Yes, it noticed when I drifted off and logged my hours resting, but its measures of restfulness were more forgiving than other, richer sleep-tracking monitors. The Basis Peak and Microsoft Band offered extra "REM sleep" metrics in addition to light and deep sleep. I have no way of knowing if these are true or accurate, but my typical night's sleep is pretty restless. That was reflected on other bands' sleep-tracking apps with alternating bands of "light" and "deep," while the Fitbit's sleep tracking just showed big chunks of blue with tiny, tiny, lines of interruption. There's no way I slept that well. But, at least it knew when I went to bed most of the time. 

fitbit charge

(Sarah Tew / CNET)

Fitbit's app: Versatile, but could be better 

The Fitbit app is nothing if not versatile: it runs on iOS, Android and Windows, and you can sync with Windows or Mac, too: an included USB dongle syncs to your computer wirelessly, or you can connect via Bluetooth provided your phone supports Bluetooth 4.0. Connecting the Fitbit on an iPhone was relatively easy, but getting always-on notifications and syncing to pair took a few attempts.

The app also connects with a ton of third-party applications, making it one of the most plugged-in ecosystems around. That's great, and the app is as cleanly designed as always, but I'm still left a little underwhelmed.

The app's basic list of steps, calories, distance, and heart rate, and its spin-off charts, doesn't do as good a job of synthesizing all the data into one summary as I would have liked. Similar to the Microsoft Band, the key data points are presented in a list. From there, you can see daily or weekly or monthly progress in any area. The Android version of the app seems to pop out its charts better than on iOS, at the moment. 

fitbit charge

(Sarah Tew/ CNET)

Heart rate is the problem area, to me. On the Fitbit iOS app, heart rate is presented as a series of daily chart readings, with heart rate squiggling throughout the day. Daily tallies of heart rate activity by yellow, orange or red zone are also added up. There's also a chart of resting heart rate over time. Information is clearly laid out.

What it all means, though, becomes harder to glean. Fitbit doesn't point to daily goals in heart rate, or show coaching advice. It feels a bit arcane for a newcomer to fitness. Earning achievements for steps taken or distance traveled is one thing, but doing that in a heart-rate-based ecosystem doesn't seem to carry over. I expected a welcome mat to be extended, helping me set up a clear plan, and helping me analyze my activity. None was really rolled out. I felt like I was staring at data, rather than understanding the bigger picture. 

fitbit charge
(Sarah Tew/ CNET)

Similarly, for sleep tracking, I wasn't getting an easily distilled summary of average hours of sleep, and guide of how and when to sleep better. Jawbone, Basis and other fitness apps do this. Fitbit's app is good, and offers plenty of customizations -- turning heart rate on or off, setting up tap gesture shortcuts on the Fitbit, and tracking food, water, weight, but the whole experience now feels a step behind the times. I want something predictive, intelligent and distilled.

Battery life: Five days, more or less 

I was able to get a solid five days of use out of the Fitbit Charge HR, while continuously connected and measuring heart rate, and with notifications turned on. That's what Fitbit claims. It's two days less than the week or so the non-heart-rate-measuring Fitbit Charge lasts. Five days is better than the Basis Peak watch and the Microsoft Band.

fitbit charge

(Sarah Tew/ CNET)

Is the Fitbit Charge HR worth it? 

For only $20 more than the heart rate-free Fitbit Charge, the Charge HR seems like a good deal. But in practice, a lot of what the heart-rate element promises is hard to figure out. I didn't know how to use heart rate to make me healthier or motivate my activity. It's easy to track 10,000 steps. It's harder to gamify heart rate.

If the Fitbit did that better, and dangled the fitness carrot on a stick in ways that motivated me more, I might love it more. As it is, it's the best all-day heart-rate-tracking casual-use fitness band that's currently available...but it could have been even more.

Singapore Sports Council logo

Live Better Through Sport - Sport Singapore recognises the value of sport in advancing the national priorities of developing our people and bonding our communities.


Singapore Sports Council location map

3 Stadium Drive, Singapore 397630