Expert Review: The Fitbit Flex

I’m training to move a sports car singlehandedly. Given that it weighs, on average, 3,500 lbs, I think that’s a nice goal for a next-generation superwoman.

But I have a teeny problem: my Fitbit Flex doesn’t want to log my heavy weight training as active minutes. I could potentially go in and log my workout manually. And yet, I’m a little lazy. So what am I supposed to do?

You see, the Fitbit Flex is your run-of-the-mill activity monitor, a step above the pedometer. Which is good, of course, if that’s what you’re looking for. And, like the untold number of other consumers who thought a fitness monitor would kickstart the inevitable New Year’s resolution, the Gizko team got a pair of Flexes over the holidays. Wearable activity monitors are super trending at the moment, and given the explosion of newly-unveiled products at the 2014 CES in Las Vegas, we decided it was time to take a look at one of the current market leaders.

As shown above, the Fitbit Flex is a little tracking device tucked into a lightweight, rubber wristband. It tracks your step count, estimates calorie burn, and records sleep patterns. Most of the other wearable monitors offer similar functionality. The question is: is it actually useful? After two weeks of continuous use, let’s see how it stacks up.


  • Super unobtrusive, adjustable wristband that comes in two sizes:  small (5.5-6.9 in / 140-176 mm) and large (6.3-8.2 in / 161-209 mm)
  • Comes equipped with a display screen of five LED lights, which sequentially light up as you accomplish each 20% of your daily step goal
  • Water resistant and submersible up to 10 meters, good for running in the rain or for those lazy users who can’t be bothered to remove it prior to showering (you know who you are)
  • You can program the Flex to wake you up silently at a preset time, when it vibrates against your wrist to shock you into wakefulness
  • It also buzzes at you when you’ve reached your daily goal, lighting up and doing a little FlexyFlex dance on your wrist to celebrate
  • Bluetooth 4.0 capability allows you to wirelessly sync data without the hassle of removing the device and plugging it in manually
  • Syncs with your iOS and Android smartphone via the Fitbit app, letting you check up on your stats even when away from your computer and its connected USB port dongle


  • Short battery life, allowing around 5 days of continuous use. I’d like for it to last at least a week, please. Those of us not glued 24/7 to our computers will find it annoying to wait for it to charge fully.
  • Precisely because of the wristband’s close comfort, it is a huge pain to reattach the band once taken off. The clasp requires some extreme contortionist moves and strong pressure to resecure.
  • The device is water resistant, but remember, the tracker comes separate from the wristband holder. So, while water won’t damage the electronics, it does get into all those nooks and crannies. And then, for some reason, unless you dry it out really well, the wristband ends up smelling like stale street water. Just sayin’.
  • The Fitbit app is a little lackluster compared to the graphs and information spread. I wish it were possible to expand the individual step, distance, calories consumed, etc. sections just like you can on the web version. Furthermore, the graphs aren’t really useful for anything beyond looking pretty. The data can’t be used to improve actual statistics nor are they really helpful for projecting future activity–unless, of course, you’re a robot with a very strict programmed routine.
  • The Flex has silent alarms, but unlike its competition, the Jawbone UP, it doesn’t wake you based on your sleep cycles. It’s just a normal alarm clock that buzzes on your wrist. Seems like a wasted capability, given the sleep tracking already built into the device.
  • It syncs via Bluetooth 4.0, but the Fitbit app syncing is only available for the iPhone and a limited array of Android phones. And Windows smartphones? Forget about it.

The Design


I really appreciated the sleek, nearly invisible wristband that housed the Fitbit’s tracking device. With colors ranging from black to tangerine and lime, the Flex’s wristband was a definite success factor for me as a typical consumer. I’m not an athlete; I’m a desk jockey. I spend a lot of time typing or writing, so its thin underside and lack of bulk proved important. Futhermore, I have small wrists. Some men might not have any issues with other wearable wrist technology being the size of a baby penguin, but a normal-sized watch face would have already been far too large and unwieldy for me.

The Hardware

The Flex houses a MEMS 3-axis accelerometer, as well as a vibration motor. It can withstand a range of temperatures, from -4° to 113° F (-20° to 45° C). It also operates at a maximum altitude of 30,000 feet (9,144 m).

The Software

The web version is lovely, with a fresh, easy-to-use layout. Colors (blue, orange, and green) indicate your progress over the day, and if you hit your goals in each section, you see a happy, green smiley face to reaffirm your awesomeness!

On the otherhand, the smartphone version is sadly lacking. It looks like this:

app version

It has expandable windows for each category, which bring you to the graph or log window. I really liked the water consumption log, as I have a tendency to forget to drink enough water every day. And while the sleep tracking isn’t much help for an insomniac, it’s interesting to see how restless I am when I do manage to sleep. Using that data, I can then adjust specific lifestyle factors (like timing of caffeine consumption, exercise frequency, and blue light exposure) and measure the potential effects on my sleep quality. On the other hand, there was a decided lack of fresh food options in the food log, which I found annoying, since I often had to approximate my intake based on the restaurant dish choices. Although I understand that is not a calorie-counting site, it is nigh impossible to make use of their “calories in/calories out” capability unless you eat out a lot. Perhaps Fitbit should team up with one of the popular calorie-counting sites to offer a more comprehensive service?

The Decision

Overall, if you’re looking for a wearable device to remind you to get moving, the Fitbit Flex may prove a good option. I do like that actively logging my movement reminds me to move a little bit more every day. In fact, I can confidently say that I move an average of 20-30% more with this little tracker than without. However, I predict that the majority of excited new users will slowly stop using it as the glamor of exercise-tracking wears off and New Year’s resolutions fall by the wayside.

Do you need a glorified pedometer? Depends on your personality. There are also apps for your smartphone that offer similar functionalities, but the Flex has the added bonus of tracking your daylong activity even when you can’t be bothered to do it yourself. The next wave of smartbands aim to make themselves more integrated in your life, so it will be harder to forget about them. But if you’re impatient, or just want a cheaper option at $99 retail, the Fitbit Flex is not a bad choice at all.

Gizko Grade: 3.9/5.0