If you’ve been reading me for awhile, you know I’m a big fan of the BodyBugg/BodyMedia device. It was the original, invented by Astro Teller, grandson of physicist Edward Teller. The BodyMedia armband uses galvanic skin response to monitor skin temperature, skin moisture, and emitted gases. Calorie expenditure was tested to be within 10% accuracy of clinical methods. Before introducing a consumer product, BodyMedia originally provided metabolic assessment services to the healthcare research market.
The BodyMedia armband was originally called a “sensewear device” but the market is now exploding as wearable “activity trackers.” Fitbit, Garmin Vivofit, and the Jawbone UP are easy to wear wristbands or clip-ons. They use the technology introduced in game devices like the Wii; they see your movements in space and apply algorithms.
Activity trackers are projected to be one of the hottest gifts this holiday season. I just picked up a Fitbit “Charge” and I’m pulling out the BodyMedia armband to make a side-by-side activity tracker comparison. I’ll be wearing them both over the next couple of weeks to see how the daily stats compare. Unfortunately, I won’t be able to find out which one is actually closest to clinical results but it will be interesting to see how close the stats are.
The BodyMedia armband tracks calorie burn, steps, and minutes of activity, measured in METs (metabolic equivalents. Click to see my blog post about METs here.) The Fitbit Charge tracks calorie burn, steps, and activity minutes in METs as well but also monitors your sleep and will (sorta) log stairs by number of floors climbed.
Both devices come with their glitches. The BodyMedia counts steps as a heel-toe stride. It has trouble tracking real stairs but does log my stepper. I’ve already observed a quirk of the Fitbit. Yesterday, it credited me with two floors of stairclimbing when I took the escalator to an EL train platform. The Fitbit measures atmospheric pressure to determine a change in elevation. It assumes that average floors are 10′ in height. I don’t see a lot of value in logging floors climbed. I’d rather see steps. I have observed that the Fitbit will log a real stairstep as a step but has trouble with stepper/Stairmaster steps.
Both devices will log every step throughout the day and they can really add up but it takes an increase in energy expenditure to log METs and get credit for “Activity” minutes. The Fitbit Dashboard for checking your stats is well-laid out. You can check it online or your phone. The BodyMedia offers similar dashboards but charges a subscription fee. The fee has prompted a programmer to offer a “FreeBugg” hack so users can stop paying the monthly fees. The BodyMedia has one feature that’s actually my favorite and the Fitbit has a similar function. I set a “Trip” feature to check my stats for a specific time period, great for seeing how many steps and calories I logged for a particular activity.It will show calorie burn per minute which I really like. It’s just the way I like to crunch the numbers. By holding down a button on the Fitbit, it will go into a “stopwatch” mode and show your stats for just that time period. It does not record these stats to the dashboard and does not show calorie burn per minute. The BodyMedia lets you see your day’s stats and “trip” stats; the Fitbit has to be switched back to regular mode.
The Fitbit’s sleep monitoring seems to be a bit buggy. There are a lot of complaints about it on the Fitbit help forum. I’ve slept with the Fitbit for the last three days and it gave me stats on my last two nights. It seems to think I rocked an all-nighter last night. I found no data when I got up this morning.
Both devices will sync and upload stats with a cable or wirelessly. For wireless transmission, the Fitbit uses this USB thingee that will definitely challenge my record of not losing stuff.
I’ll be blogging and tweeting my stats in the coming days so check back for my updates on how each of the devices are performing in daily use!