The state of affairs
Companies in the fitness arena love peddling the capabilities of their latest tracking devices, and that can make it hard to tell where the truth ends and the hype begins. A "three-axis accelerometer" sounds impressive enough, but it boils down to a very simple piece of hardware that you can find in pedometers selling for under fifteen dollars and likely just as accurate as their more expensive counterparts (which, as we’ve seen in our own testing, aren’t particularly accurate to begin with).
To me, the real value of these devices isn’t in the accuracy of their tracking alone, but rather in the way they integrate credible, roughly accurate tracking with social and motivational features. Ultimately, this is how these devices get you off your butt and running while the $15 pedometers don’t.
When a couple months ago I decided to buy a fitness tracker, my research made me doubt the usefulness of tracking sleep with a naked accelerometer (experts say there’s no relationship between sleep phase and movement, making accelerometer-based trackers more or less useless in that regard). So I went with the unassuming $49 Fitbit Zip instead of the higher-end options which have more features on paper, but not much hardware to actually provide credible data.
The Jawbone UP3 wearable wristband, however, could really change the game: the company promotes it as the "world’s most advanced fitness tracker" and, for once, there’s a chance this may be truth and not hype.
Compared to your average tracker, the UP3 adds several new sensors. Bioampedance sensors, which measure the resistance of tissue and blood flow from the wrist, will be able to track resting heart rate, respiration and levels of sweat (via galvanic skin response); when you combine this with two additional skin and ambient temperature sensors, you can get quite a comprehensive picture of your level of activity, with a depth that goes above and beyond the capabilities of a simple accelerometer.
Unlike the previous model, the UP3 will be water-resistant up to 10 meters (33 ft), which should be adequate for most swimming. Battery life is "up to 7 days" after a 100-minute charge via a USB cable, although you won’t need to connect a cable to sync the bracelet’s with the Jawbone app.
There’s no screen on the device; however, three LED indicators will tell your "mode status" - blue for sleep, orange for activity, and white for notifications.
The software side of things is interesting as well. Besides making use of the Jawbone app, which is perhaps the best-looking of the bunch, the UP3 attempts to automatically recognize your current activity based on the input of its sensors. The general gripe with most wrist-worn trackers is that any casual hand movement will count as a workout; perhaps Jawbone can use the wealth of sensors packed on the UP3 to filter out some of the noise. According to the company, the system also learns from your behavior over time to auto-classify other harder to recognize activities like swimming, cycling, weights or yoga. Finally, free over-the-air software updates promise to also deliver passive and on-demand heart rate.
It goes without saying that I can’t speak to the accuracy of the UP3, which is due to launch later this year, or as to whether it can accurately track all four phases of sleep like Jawbone claims. For instance, in tracking resting heart rate, the company said it chose to use bioampedance sensors instead of the optical sensors featured in the yet-to-be-released Fitbit Charge and Apple Watch. Jawbone says it did this to save power and achieve that 7-day battery life, but there may be accuracy tradeoffs.
However, when you compare its wealth of sensors to those in other fitness trackers, there’s at least reason to be optimistic. At the very worst, you’ll be able to geek out on a lot more stats than ever before.
The UP3 will be available later this year for US$179.99 in black, with additional colors, including silver, coming sometime next year.