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Computerized Investing > August 18, 2012

BodyMedia FIT CORE Armband + Activity Manager

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by Wayne A. Thorp, CFA

$149.99, plus $6.95/mo. (first three months free)

Monitor your daily metabolic and lifestyle data to reach your activity and weight goals.

Technology has made our lives easier in countless ways. One of these ways is in assisting us to live healthier lives. There are a number of technologies available today to help us track our daily activity and eating habits. One of these is the BodyMedia FIT CORE Armband. Equipped with sensors that monitor the calories burned during your daily activities and the quality of your sleep, the online Activity Manager allows you to track this information, log your food intake and see your personal bests.

Out of the Box

The BodyMedia FIT Armband package comes with a BodyMedia FIT CORE Armband monitor, armband strap, micro-USB cable, manual and quick-start guide. The FIT CORE monitor measures 2.6 inches by 1.6 inches by 0.7 inches and has a curved shape. It pops into a ring that is attached to the adjustable elastic armband. Weighing only 0.6 ounces, it is hardly noticeable when you are wearing it.

When not in the armband holder, there is a mini-USB port on its edge that is used to plug into your computer to charge and sync it with the Activity Manager.

On the top of the FIT CORE is an indicator light and a status button. When you press the button, the indicator light is green, which means the armband is ready to monitor your activity. A slow flashing amber light indicates the armband has less than 24 hours of battery or memory remaining. When the indicator is flashing red, the armband is not able to collect data and you need to plug it into a computer to charge it or upload data.

The device has four sensors for collecting data regarding your activity and calories burned. The sensors can capture over 5,000 data points per minute. There is an internal 3-axis accelerometer along with two metal contacts on the bottom of the armband housing three sensors, which measure skin temperature, galvanic skin response (how much you're sweating) and heat flux (how fast heat is dissipating from your body).

Missing from the FIT CORE, though, is a heart rate monitor. According to BodyMedia, they chose to omit a heart rate monitor because they felt it did not add to the overall accuracy of its calories burned and activity measurement. Instead, they argue such a sensor would only add to the cost and weight of the device. However, BodyMedia has added compatibility with select heart rate monitors, which allows you to import the data into your Activity Manager so you can evaluate your calories burned and heart rate during workouts.

The internal lithium battery takes about three hours to charge and lasts about four to six days. The memory capacity holds about two weeks’ worth of data.

The device can detect when you are wearing it. Within a few minutes of putting it on the tricep of your left arm, it emits a series of tones indicating that it is recording data from your body.


Before you can make use of the data that the FIT CORE collects, you must set up an account and subscription. With the purchase of the FIT CORE, you get three months of free access to the BodyMedia Activity Manager. After that, the cost is $6.95 a month. Undoubtedly, some will not be happy with having to spend a monthly fee to make their $150 purchase useful, but this is consistent with other similar device makers.

After you have signed up for your account, you can log in to the BodyMedia website. You can enter such information as your gender, height, weight and typical activity level (sedentary, moderately active, very active, etc.).

Activity Manager

The Activity Manager reports the data recorded by the armband so you can keep track of your progress toward your activity and weight goals. You can track daily calories burned, steps taken, time spent in moderate or vigorous activity, nutritional analysis and sleep efficiency. This is ultimately what your monthly subscription fee pays for.


I’ve been using the BodyMedia FIT CORE device that was given to me by the company for nearly a month. It is so light that you hardly know you are wearing it. Its profile is such that it can also be worn under clothing, making it rather inconspicuous. I’ve read some reviews that say the device left marks on your arm, but that wasn’t the case with me. Even after wearing it for nearly a day, including while sleeping, there was no indication I had worn it. The FIT CORE measured my calories burned, amount of moderate and vigorous activity each day, number of steps taken and my sleep time. According to BodyMedia, the FIT CORE is 90% accurate in measuring calories burned, 95% accurate in measuring the amount of physical activity and 91% accurate in measuring the number of steps taken each day. When it came to measuring sleep time, however, there was a slight hiccup. Similar to a couple of other reviews I’ve read, the device hasn’t been reliable in tracking my sleep habits.

Also, though somewhat tedious, the Activity Manager’s food log was easy to use.

Final Verdict

If you are someone who needs a nudge to be more active, or if you are someone looking to keep track of your overall physical activity, then the BodyMedia FIT CORE is well worth the money. I’ve been using it for over a month and have found myself motivated to burn more calories and take more steps than I did the previous day. If one of the goals of fitness devices is to get you to be more active, the BodyMedia FIT CORE Armband does just that.


  • Accurately records calories burned, steps taken
  • Long battery life
  • Comfortable design


  • Subscription required
  • Trouble tracking sleep
  • No heart rate monitor

BodyMedia FIT CORE Armband + Activity Manager

$149.99, plus $6.95/mo. after three months

Wayne A. Thorp, CFA, is the author of "Gadget Corner." All reviews are based on firsthand experience of the product or service. No third-party compensation is received for opinions on products, services, websites or topics. However, sometimes the author is not required by the manufacturer or their PR firm to return the product under review. In such instances, it is our policy to convey this within the review. The views and opinions expressed in these reviews are strictly those of the author. Any product claim, statistic, quote or other representation about a product or service should be verified with the manufacturer or provider.

Wayne A. Thorp, CFA is a vice president and senior financial analyst at AAII and editor of Computerized Investing. Follow him on Twitter at @WayneTAAII.


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