The Basis B1 band, from BASIS Science, is a digital watch that continuously measures your health, 24 hours a day.
The Basis B1 band has a 3-axis accelerometer that measures motion (similar to pedometers or Jawbone's UP), but it packs on four more sensors to get a far more thorough and more accurate handle on your health. An optical sensor visually detects changes in blood flow in the skin to determine pulse (which it displays on its watch face). A galvanic skin response sensor determines sweatiness. And the band has two thermometers: one that measures your temperature and one that measures the environment's temperature.
The watch uploads all that data to the cloud, where software streamlines it into an easy-to-read website that displays calories burned, steps, time slept, heart rate, health points. The company expects the band to go on sale early this year for $199.