As is becoming the trend, the portion of Apple's WWDC conference dedicated to the Apple Watch featured a heavy focus on the watch's health and fitness features, which continue to be the wearable's hallmark feature set. 

"Apple Watch is designed to help you live a healthier life," CEO Tim Cook said, "and people are absolutely loving the fitness capabilities, the health capabilities, the quick access to information, and even the ability to swim with it."

The biggest update to the Apple Watch health and fitness suite was an integration between the watch and fitness equipment at the gym. Brands like LifeFitness, Matrix, TechnoGym, Star Trac, Cybex, Schwinn, and StairMaster, which sell 80 percent of the country's fitness equipment, will start to roll out Apple Watch-integrated equipment this fall.

"When you use gym equipment it has data the Apple Watch doesn’t have, and the Watch has data the gym equipment doesn’t have, so you end up with numbers like calories and distance that don’t quite match," Apple VP of Technology Kevin Lynch said. "In WatchOS 4 we’ve come up with a great solution to this. We’re enabling, for the first time, two-way data exchange in real time with gym equipment. You’ll be able to simply tap your Apple Watch on an NFC reader in your gym equipment, and your Watch will automatically launch the workout app. Then your heart rate is read by the watch and sent to the equipment, and data like incline and speed is sent from the equipment to your watch. So now all the information matches, it’s much easier and it’s a lot more accurate."

Another update is to the Apple Watch's coaching features, which will now be more personalized to the user, telling them what achievements they might be close to, reporting how close they are to matching yesterday's metrics, and even calculating achievable goals based on past performance. The graphic that displays when the rings are closed or an achievement is reached have been updated to be flashier.

Swimming tracking has been improved by automatically adding sets when the swimmer takes a break at the end of a lane. Apple has also added high-intensity interval training to the Watch and it's now possible to set up a queue of workouts to fire one after another, which could be helpful for something like triathlon training. 

Finally, the watch is adding native Bluetooth to be able to communicate with third party devices. Lynch specifically mentioned continuous glucose monitoring from Dexcom as an app that will benefit from this new feature. Dexcom has an Apple Watch app at the moment, but it currently requires the phone to be in range. Now the Watch and the CGM will be able to communicate directly.