BodyMedia is launching a cool looking health-tracking band that you can wear on your arm. The new BodyMedia Core 2 band packs four sensors into a small housing.

We’ll see a lot of such health-tracking devices at the Consumer Electronics Show this week in Las Vegas, where press events are already underway. But BodyMedia promises it will be the smallest wearable multi-sensor device of its kind and the first to offer a choice of interchangeable jewelry.

The housing for the device is smaller than an iPod Nano music player, and you can attach cool looking faceplates, straps, and cuffs to make it look more fashionable. It features sensors to measure heart rate, temperature, heat flux, galvanic skin response (sweat), and motion. The three-axis accelerometer gets an accurate measure of your steps. Altogether, the system uses the data from the sensors to calculate your calorie burn, exercise intensity, and sleep patterns.

The original Core armband was used on The Biggest Loser television show to track the fitness of contestants. The new device has energy-saving Bluetooth Smart technology that allows it to send activity updates to your smartphone or tablet. It can do so with longer battery life.

With the smartphone and tablet, you can use an app that makes sense of the data and interprets it so you can make smarter decisions about food, exercise, and other things health-related. The company is showing a prototype at CES for the first time today, but the new model won’t ship until August.

The system is not unlike the just-launched Basis Health Tracker from Basis Science. Other rivals have also hit the market, but BodyMedia has upped the ante by adding so many sensors, which capture more than 5,000 data points per minute. The heart-rate monitor is an extra option that you have to purchase separately. The monitor is included in an accessory strap with an embedded heart-rate sensor.

Besides the armband, the system comes with a free mobile app, an online Activity Manager that you can log into via the web, and personalized feedback with the BodyMedia FIT coach. The web site gives you historical data about your activity and sleep, with dietary adjustment recommendations based on your weight goals.

BodyMedia says its earlier monitoring technology has been clinically validated, improving weight loss up to three times over behavioral support alone. It is FDA-registered as a medical device. BodyMedia was founded in 1999 and is based in Pittsburgh, Pa. CES press events are being held Sunday and Monday, and the show floor opens on Tuesday.

Mio Global is launching a heart-rate monitor and wristwatch dubbed the Mio Alpha. The company claims it is the first performance-level strapless monitor that can measure your heart rate accurately at speeds up to 12 miles per hour. The company is pitching the $199 at both professional athletes and those of us who are serious about getting into shape.

The device comes from Vancouver, Canada-based Mio Global, which raised $321,314 in a Kickstarter campaign for the Mio Alpha in August. The company was created in 1999 by entrepreneur Liz Dickinson, a mother of three. She designed the Mio family of heart-rate monitor watches. With the early watches, the user touched the sensor on the face of the watch to get a reading. With the Mio Alpha, the company says it can display an EKG-accurate heart rate on the watch continuously, even at high speeds.

The Mio Alpha uses Bluetooth Smart wireless to connect with compatible smartphones and fitness devices. Users can set heart-rate zones and receive visual and audible alerts when they hit them. The can review data from exercises, including total exercise time, average heart rate, and time “in the zone.” The company says that the Alpha’s accuracy has been tested by Philips Electronics and a test facility at the University of Maastricht in the Netherlands. By tracking your heart-rate accurately, you can control the intensity of your workout and discover what areas might need extra attention. Such knowledge helps athletes know when they are under-training or over-training.

Mio says it will certify specific development partners who form an alliance with it. It competes with a number of other devices, including the Basis Health Tracker, which Basis Science launched last week.

The Mio Alpha uses electro-optical technology to sense the heart beat. Similar technology is used in hospitals to monitor heart rates, but the systems can’t be used by people in motion. The Mio Alpha uses two light beams and an electro-optical cell to “sense” the volume of blood under your skin.

“Because the blood volume pulsates in the rhythm of the heart, so does the signal from the electro-optical cell,” the company said in its Kickstarter campaign. “This signal is processed by an advanced electronics circuit and passed on to a highly specialized computer program that is embedded in the Alpha. To date, the stumbling block with this type of technology has been that arm movements while walking or running strongly interfere with the electro-optical signal to the point that it is no longer possible to extract the heart rate from it. In order to solve this problem the Alpha has been provided with a separate motion detector.”

The company added, “The computer program is able to use the information from this detector to compensate for the disturbance that is generated in the electro-optical signal by walking or running motions. As a result, the Alpha can display an accurate heart rate even during motion intense activities.”