Back in September, when we first heard about the Apple Watch, we were intrigued. Not just because it can be customized with that, uh, unique lime-green band — but also because it could be a way to smoosh everything we want from a fitness tracker into everything we want from a smartwatch, making the aforementioned tracker pretty unnecessary. At today's keynote address, we got a few more enticing tidbits about how the Apple Watch — what Tim Cook called a "comprehensive health and fitness companion" — could change the way we work out: 1. The watch has a heart rate sensor. This is becoming the standard on newer fitness trackers because it's so helpful in accurately calculating how hard you're working. 2. Using a gyroscope and accelerometer, the Apple Watch will measure your activity throughout the day. But, by also tracking elevation, it can distinguish between different types of activities — including cycling, rowing, and pretty much anything else you'd find in a gym. 3. You'll get rewarded with lovely little fitness badges every time you complete a goal. Positive reinforcement? Yes, please. 4. Apple's own Activity and Workout apps keep track of all your data and share it with the Health app. From there, you can choose whether to share your info with other third-party apps, including those in the ResearchKit, which allow you to take part in clinical studies. 5. Overall, the watch tracks your basic movement (e.g. steps), your exercise, and how long you're not active. It even reminds you to stand up every once in a while. Finally, it sends you weekly summaries of your stats, plus suggestions for how to improve in the upcoming week. With all of this, we'll be able to make staying active a hassle-free priority. Now, we just need that lime-green band.