Apple Introducing  Watch - Film - 2014, September 9

An intelligent health and fitness companion.
Apple Watch gives you a more complete picture of your all-day physical activity because it measures more than just the quantity of your movement, such as the number of steps you take. It measures the quality and frequency as well. The three rings of the Activity app show your progress at a glance, and provide all the motivation you need to sit less, move more, and get some exercise. There’s also a separate Workout app for dedicated cardio sessions. Over time, Apple Watch can use what it learns about the way you move to suggest personalized daily fitness goals and encourage you to achieve them. So you can live a better day and a healthier life.