Health and fitness apps can use workout sessions to remain in the foreground during an active workout and while monitoring the wearer's health, such as during sleep or while using a heart-rate monitor. As time passes between wrist raises, Apple Watch usually reverts to displaying the watch face, but when your app has an active workout session it displays your app instead.
Consider presenting a workout session as a modal experience. During a workout, people typically need only session-specific functionality — they don't need to review the list of workouts or access other parts of your app. Offering the most important items in a modal experience can help people manage their session while minimizing distraction. Here is an arrangement that many workout apps use, including Workout:
Use a distinct visual appearance to indicate an active workout. During a workout, people should be able to recognize an active session at a glance. The metrics page can be a good way to show that a session is active, because the values update in real time. In addition to displaying updating values, you can further distinguish the metrics screen by using a unique layout.
Provide workout controls that are easy to find and tap. In addition to making it easy for people to pause, resume, and stop a workout, be sure to provide clear feedback that indicates when a session starts or stops.
Help people understand the health information your app records when sensor data is unavailable. For example, water may prevent a heart-rate measurement, but your app can still record data such as the distance people swam and the number of calories they burned. If your app supports the swimming or other workout types, explain the situation using language that’s similar to the language used in the system-provided Workout app.
|Example text from the Workout app|
|GPS is not used during a Pool Swim, and water may prevent a heart-rate measurement, but Apple Watch will still track your calories, laps, and distance using the built-in accelerometer.|
|In this type of workout, you earn the calorie equivalent of a brisk walk anytime sensor readings are unavailable.|
|GPS will only provide distance when you do a freestyle stroke. Water might prevent a heart-rate measurement, but calories will still be tracked using the built-in accelerometer.|
Provide a summary at the end of a session. A summary screen confirms that a workout is finished and displays the recorded information. Consider enhancing the summary by including Activity rings, so that people can easily check their current progress.
Discard sessions that are extremely brief. If a session ends a few seconds after it starts, your app should either discard the data automatically or ask people to confirm whether the data should be discarded or recorded as a workout.
Make sure text is legible when people are in motion. When a session requires movement, your app should use large font sizes and arrange text so that the most important information is easy to read.
Use Activity rings as recommended. For guidance, see Activity Rings.
For developer guidance, see HKWorkoutSession.