Earlier this year, I invested in a FitBit One – a diminutive clip-on fitness tracker designed to monitor how many steps I take in a day, the number of stairs I climb and even how long and fitfully I sleep. It worked great until I forgot to remove it from my jeans and accidentally ran it through the wash. Then? Not so much. I've since been forced to get a new one. So when FitBit released the Flex – an iteration of their fitness tracking hardware designed to be worn as a bracelet – I was understandably eager to take it for a spin.
The $100 Flex is a masterclass in minimalistic design. Available in slate or black (additional coloured bands are sold separately,) the Flex's diminutive capsule full of hardware is nestled away in a soft-touch silicon wristband. It's so light that you'll often forget you're wearing it, and it boasts enough water resistance that you can shower or jog in the rain with it on.
The Flex's raison d'être is measuring how far you move in a day and how long you sleep – a task it performs thanks to a tri-axis accelerometer baked into the hardware. Every step you take (and when bedding down for the night, every toss and turn you make) is registered by the Flex and used to estimate how far you've travelled, how many calories you've burned and how much sleep you get in a 24-hour period. This information can stored on the device for up to seven days at a time, and can be uploaded to a computer and a handful of smartphones via a Bluetooth 4.0 connection. Once the Flex's data has been transferred, you can view it via your account on FitBit's homepage, or on a smartphone provided you have an iPhone or compatible Android handset.
The Flex has a display, but the information it can provide is minimal. Your daily progress towards achieving your fitness goal (a user decided total number of steps per day,) is illustrated through the use of a small array LEDs. The more LEDs displayed, the further along you are.
The FitBit Flex's battery will last anywhere from five to 10 days before it requires recharging. The amount of battery life you get out of the device is dictated by how you use it: Frequent use of the device's display or using it's built-in vibrating silent sleep alarm (perfect for waking up quietly without disturbing your partner,) will reduce the battery's runtime.
Despite everything that the Flex is, it's difficult to overlook what it isn't.
In addition to a tri-axis accelerometer, The Flex's immediate predecessor, the FitBit One, also had a built in altimeter to measure when its user was climbing or ascending a set of stairs, and a display that could show the time, number of steps taken, calories burned and distance travelled per day. What's more, the One costs the same as the Flex. I understand that the absence of these features made it possible for FitBit to shrink the Flex down to insanely svelte dimensions, but I can't help but feel the device is a step backward.
I found that the Flex wasn't as accurate as the One, and often registered significantly more steps per day than the older tracker did. This was due, no doubt, to the lack of an altimeter and the fact that the wrist-worn Flex also registered the movements of my arm while sitting in addition to my forward momentum while walking. This, along with it's lack of display capable of providing meaningful information made the Flex feel somewhat lacking when compared to the older FitBit One. It's worth mentioning that it also lacks many of the features built into hardware from such competitor devices as Jawbone's Up and Nike's Fuelband.
With less accuracy and fewer features than similarly priced hardware, the FitBit Flex feels more like a novelty when measured against other popular wearable fitness trackers. And newer, more capable devices on the horizon will be capable of providing even more information on a wearer's heart rate, calories burned, stress level and breathing patterns. You'd be better off buying The FitBit One, or alternately, waiting for something better to come along.