In Apple Healthkit, Workout totalEnergyBurned is Deprecated but activeEnergy Returns Null: What You Need to Know

Are you developing a fitness app that integrates with Apple Healthkit? Have you noticed that the totalEnergyBurned property of the HKWorkout object is deprecated, and the activeEnergyBurned property returns null? Don’t worry, you’re not alone! In this article, we’ll delve into the reasons behind this change, provide workarounds, and offer tips on how to migrate your app to use the new energy metrics.

What’s Happening with totalEnergyBurned?

The totalEnergyBurned property, which was introduced in iOS 9, provided the total energy expenditure of a workout in kilocalories (kcal). However, with the release of iOS 14, this property has been deprecated. Apple recommends using the activeEnergyBurned property instead, but what if it returns null?

Why totalEnergyBurned Was Deprecated

The main reason for deprecating totalEnergyBurned is that it was not accurate enough. The property was calculated based on the workout’s duration, intensity, and user’s metadata, such as age, sex, weight, and height. However, this calculation was oversimplified and didn’t take into account individual variations in metabolism, fitness level, and other factors that affect energy expenditure.

Moreover, the totalEnergyBurned property was often misinterpreted as the total caloric expenditure, which is not the same as the energy expenditure during exercise. Apple realized that this property was causing confusion and decided to replace it with a more accurate and granular measurement.

Understanding activeEnergyBurned and Other Energy Metrics

The activeEnergyBurned property, introduced in iOS 14, provides the energy expenditure during exercise in kilocalories (kcal). This property is more accurate than totalEnergyBurned, as it’s based on the user’s activity data and takes into account the intensity and duration of the workout.

However, what if activeEnergyBurned returns null? This might happen if the user hasn’t granted permission to access their activity data or if the workout data is incomplete. In this case, you can use the following energy metrics as a fallback:

• HKQuantityTypeIdentifierDistanceWalkingRunning: This metric provides the distance traveled during walking or running activities.
• HKQuantityTypeIdentifierFlightsClimbed: This metric provides the number of flights climbed during staircase activities.
• HKQuantityTypeIdentifierBasalEnergyBurned: This metric provides the resting energy expenditure, which is the energy expended by the body at rest.

Note that these metrics are not as accurate as activeEnergyBurned, but they can still provide a rough estimate of the user’s energy expenditure.

Workarounds for Deprecated totalEnergyBurned

If your app is still using totalEnergyBurned, you’ll need to migrate to activeEnergyBurned or other energy metrics. Here are some workarounds to help you transition:

1. Use the HKWorkout.totalEnergyBurned property only for iOS 13 and earlier devices. For iOS 14 and later devices, use HKWorkout.activeEnergyBurned.

2. Implement a fallback mechanism that uses other energy metrics, such as distance walked or flights climbed, if activeEnergyBurned returns null.

3. Use a third-party library or service that provides more accurate energy expenditure estimates, such as those based on machine learning algorithms.

Migrating Your App to Use activeEnergyBurned

To migrate your app to use activeEnergyBurned, follow these steps:

// 1. Create an HKWorkout object
HKWorkout *workout = [[HKWorkout alloc] initWithActivityType:HKWorkoutActivityTypeRunning
                                                 startDate:start Date
                                                   endDate:endDate
                                                  duration:duration];

// 2. Set the workout metadata
[workout setMetadata:@{@"HKWorkoutMetadataKeyDistance": @(1234)}];

// 3. Add the workout to the HealthKit store
[healthStore saveObject:workout
             withCompletion:^(BOOL success, NSError *error) {
                 if (!success) {
                     // Handle the error
                 }
             }];

// 4. Retrieve the activeEnergyBurned value
HKQuantity *activeEnergyBurned = [workout valueForKey:@"activeEnergyBurned"];

if (activeEnergyBurned) {
    // Use the activeEnergyBurned value
} else {
    // Use a fallback mechanism
}

Bonus: Tips for Accurate Energy Expenditure Estimates

To get the most accurate energy expenditure estimates, follow these tips:

Tips	Description
Use device-based data	Integrate with Apple Watch or other devices that provide activity data, such as GPS, accelerometer, and gyroscope.
Collect additional metadata	Collect user metadata, such as age, sex, weight, and height, to improve the accuracy of energy expenditure estimates.
Implement machine learning algorithms	Use machine learning algorithms that can learn from user data and provide more accurate energy expenditure estimates.
Provide feedback mechanisms	Allow users to correct or adjust their energy expenditure estimates to improve the accuracy of your app’s calculations.

Conclusion

In conclusion, the deprecation of totalEnergyBurned in Apple Healthkit is a step towards more accurate and granular energy expenditure estimates. By understanding the new energy metrics, implementing workarounds for deprecated properties, and migrating your app to use activeEnergyBurned, you can provide a better experience for your users. Remember to follow the tips for accurate energy expenditure estimates to get the most out of Apple Healthkit.

Stay up-to-date with the latest Apple Healthkit developments and best practices to ensure your app remains compatible and user-friendly. Happy coding!

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