It takes courage to strap this 1-oz. band around your upper arm and let it measure things like skin temperature, sweat and heat flux (the rate at which heat is coming off your body) around the clock. That’s because the $149 CORE armband, which uses the measurements to calculate total calories burned, has an uncanny knack for making you feel like a slug if you don’t move enough each day.
The rectangular, 2-in.-by-1-in. device is wireless while you wear it, but you need to plug it into your computer’s USB port to recharge and upload data (or buy the larger, $179 Bluetooth-enabled LINK armband). Once you do, you’ll see detailed charts on the BodyMedia website with hourly logs of calories burned, physical activity, steps taken and even sleep, which the armband calculates based on movement and changes in body temperature.
The biggest drawback? Having to leave the armband on most of the time. Who wants to wear a clunky armband when you’re out on a date or wearing a close-fitting shirt? And while the food-logging smartphone app is handy, it takes too long to enter nutritional information on items that are missing from the database. Nonetheless, I liked the BodyMedia Fit CORE armband better than any other device I tested because it was the only one that estimated total calories burned, even while I was asleep. Hey, every bit counts.