(Credit: Apple)

For anyone out there looking to build the latest health app, Apple's unveiling of the new Apple Watch Series 4 was a welcome surprise, as the latest iteration of the device doubles down on its years-long march toward being a more fitness-focused platform.

Apple has added a ton of new functions to the watch and given it a bunch of tools to track your health in a number of new ways.

Here are the three most important additions that may open the door to a new generation of health apps.

SEE: Apple Watch Series 4 introduces ECG app and other health upgrades

1. New tech to track heart health and falls

The new watch is the first of its kind in allowing users to get an electrocardiogram (EKG) reading just by pressing the crown. In addition to the EKG readings, which simply monitor the heart's functions, the watch can detect irregular heartbeat rhythms and let users know about it. Both features required clearance from the FDA, and their quick approval is a sign that the government is ready to accept more apps with similar testing capabilities.

The heart health features will tell users if they have any signs of dangerous conditions like atrial fibrillation, but the FDA was explicit in saying that the watch and its functions should not replace traditional tests at hospitals. Neither feature is currently available, but Apple said they will roll it out slowly through the fall.

Apple also added features catering to the elderly, creating a function on the watch that can tell if you've fallen down and call for assistance if you need.

2. New APIs for workouts, notifications, and Siri

Apple added a bunch of new features that improve Siri on the watch and make notifications significantly more interactive.

"Siri uses machine learning and relevance algorithms to understand inputs, past behavior, and routines associated with your app's users in order to show timely content or provide Siri Shortcuts -- right when they're needed. To take action, users can simply raise their wrist and tap the Siri watch face or say customized commands to Siri," Apple wrote in their release on the new watchOS.

"A new workout API simplifies workout app development, ensures improved data accuracy, and enables more robust app performance. An upcoming API will give developers and researchers access to custom algorithms based on accelerometer and gyroscope data so they can create tools that help doctors and patients better understand patients' tremor and dyskinesia symptoms in response to treatment for Parkinson's Disease."

The app's health information can be organized into separate "workout samples" that are compilations of information taken while you exercise. The watch will have Activity Rings that give users a summary of their activity that day and a breakdown of any statistics.

The update will also allow developers to make app notifications "more interactive with customized controls that let users take actions directly within the notification without opening the app."

3. 35 percent larger screen

App creators will have a lot more real estate to work with now that the latest Apple Watches have a 35 percent larger screen. With the bigger screen and more powerful processor, app creators can add everything from colorful displays to fun notifications.

"Your apps can now take advantage of the expanded display on Apple Watch Series 4 to show even more information and detail at a glance. And with enriched complications on the new Infograph and Infograph Modular watch faces, you can create vivid, full-color enriched complications," Apple wrote.

"And now with watchOS 5 and Apple Watch Series 4, you can deliver even better user experiences with enriched complications, interactive notifications, access to the Siri watch face, audio controls, and more."

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  1. The latest Apple Watch comes with a bunch of new features and functions that will open the door to a number of different fitness-apps.
  2. Among the most important changes, the watch's APIs for workouts, notifications, and Siri, as well as its larger face and heart tracking features, make it an ideal platform for health app developers.

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Jonathan is a Contributing Writer for CNET's He's a freelance journalist based in New York City. He recently returned to the United States after reporting from South Africa, Jordan, and Cambodia since 2013.